diff --git a/src/pages-and-resources/discussions/app-config-form/apps/legacy/LegacyConfigForm.jsx b/src/pages-and-resources/discussions/app-config-form/apps/legacy/LegacyConfigForm.jsx
index 983c82a91..ab89ffe66 100644
--- a/src/pages-and-resources/discussions/app-config-form/apps/legacy/LegacyConfigForm.jsx
+++ b/src/pages-and-resources/discussions/app-config-form/apps/legacy/LegacyConfigForm.jsx
@@ -1,4 +1,4 @@
-import React from 'react';
+import React, { useState } from 'react';
 import PropTypes from 'prop-types';
 import { Card, Form } from '@edx/paragon';
 import { Formik } from 'formik';
@@ -9,6 +9,7 @@ import DivisionByGroupFields from '../shared/DivisionByGroupFields';
 import AnonymousPostingFields from '../shared/AnonymousPostingFields';
 import DiscussionTopics from '../shared/discussion-topics/DiscussionTopics';
 import BlackoutDatesField, { blackoutDatesRegex } from '../shared/BlackoutDatesField';
+import LegacyConfigFormProvider from './LegacyConfigFormProvider';
 
 import messages from '../shared/messages';
 import AppConfigFormDivider from '../shared/AppConfigFormDivider';
@@ -36,6 +37,7 @@ Yup.addMethod(Yup.object, 'uniqueProperty', function (propertyName, message) {
 function LegacyConfigForm({
   appConfig, onSubmit, formRef, intl, title,
 }) {
+  const [validDiscussionTopics, setValidDiscussionTopics] = useState(appConfig.discussionTopics);
   const legacyFormValidationSchema = Yup.object().shape({
     blackoutDates: Yup.string().matches(
       blackoutDatesRegex,
@@ -72,30 +74,37 @@ function LegacyConfigForm({
           && errors.discussionTopics
           && errors?.discussionTopics[index]?.name,
         ));
+        const contextValue = {
+          validDiscussionTopics,
+          setValidDiscussionTopics,
+          discussionTopicErrors,
+        };
 
         return (
-          <Card className="mb-5 px-4 px-sm-5 pb-5" data-testid="legacyConfigForm">
-            <Form ref={formRef} onSubmit={handleSubmit}>
-              <h3 className="text-primary-500 my-3">{title}</h3>
-              <AppConfigFormDivider thick />
-              <AnonymousPostingFields
-                onBlur={handleBlur}
-                onChange={handleChange}
-                values={values}
-              />
-              <AppConfigFormDivider thick />
-              <DiscussionTopics discussionTopicErrors={discussionTopicErrors} />
-              <AppConfigFormDivider thick />
-              <DivisionByGroupFields discussionTopicErrors={discussionTopicErrors} />
-              <AppConfigFormDivider thick />
-              <BlackoutDatesField
-                errors={errors}
-                onBlur={handleBlur}
-                onChange={handleChange}
-                values={values}
-              />
-            </Form>
-          </Card>
+          <LegacyConfigFormProvider value={contextValue}>
+            <Card className="mb-5 px-4 px-sm-5 pb-5" data-testid="legacyConfigForm">
+              <Form ref={formRef} onSubmit={handleSubmit}>
+                <h3 className="text-primary-500 my-3">{title}</h3>
+                <AppConfigFormDivider thick />
+                <AnonymousPostingFields
+                  onBlur={handleBlur}
+                  onChange={handleChange}
+                  values={values}
+                />
+                <AppConfigFormDivider thick />
+                <DiscussionTopics />
+                <AppConfigFormDivider thick />
+                <DivisionByGroupFields />
+                <AppConfigFormDivider thick />
+                <BlackoutDatesField
+                  errors={errors}
+                  onBlur={handleBlur}
+                  onChange={handleChange}
+                  values={values}
+                />
+              </Form>
+            </Card>
+          </LegacyConfigFormProvider>
         );
       }}
     </Formik>
diff --git a/src/pages-and-resources/discussions/app-config-form/apps/legacy/LegacyConfigFormProvider.jsx b/src/pages-and-resources/discussions/app-config-form/apps/legacy/LegacyConfigFormProvider.jsx
new file mode 100644
index 000000000..72ac50f82
--- /dev/null
+++ b/src/pages-and-resources/discussions/app-config-form/apps/legacy/LegacyConfigFormProvider.jsx
@@ -0,0 +1,26 @@
+import React, { createContext } from 'react';
+import PropTypes from 'prop-types';
+
+export const LegacyConfigFormContext = createContext({});
+
+export default function LegacyConfigFormProvider({ children, value }) {
+  return (
+    <LegacyConfigFormContext.Provider value={value}>
+      {children}
+    </LegacyConfigFormContext.Provider>
+  );
+}
+
+LegacyConfigFormProvider.propTypes = {
+  children: PropTypes.node.isRequired,
+  value: PropTypes.shape({
+    discussionTopicErrors: PropTypes.arrayOf(PropTypes.bool),
+    validDiscussionTopics: PropTypes.arrayOf(PropTypes.shape({
+      validTopics: PropTypes.arrayOf(PropTypes.shape({
+        name: PropTypes.string,
+        id: PropTypes.string,
+      })),
+      setValidDiscussionTopics: PropTypes.func,
+    })),
+  }).isRequired,
+};
diff --git a/src/pages-and-resources/discussions/app-config-form/apps/shared/DivisionByGroupFields.jsx b/src/pages-and-resources/discussions/app-config-form/apps/shared/DivisionByGroupFields.jsx
index a213740c1..21aac43f0 100644
--- a/src/pages-and-resources/discussions/app-config-form/apps/shared/DivisionByGroupFields.jsx
+++ b/src/pages-and-resources/discussions/app-config-form/apps/shared/DivisionByGroupFields.jsx
@@ -1,13 +1,14 @@
-import React, { useEffect } from 'react';
-import PropTypes from 'prop-types';
+import React, { useEffect, useContext } from 'react';
 import { injectIntl, intlShape } from '@edx/frontend-platform/i18n';
 import { Form, TransitionReplace } from '@edx/paragon';
 import { FieldArray, useFormikContext } from 'formik';
 import FormSwitchGroup from '../../../../../generic/FormSwitchGroup';
 import messages from './messages';
 import AppConfigFormDivider from './AppConfigFormDivider';
+import { LegacyConfigFormContext } from '../legacy/LegacyConfigFormProvider';
 
-const DivisionByGroupFields = ({ intl, discussionTopicErrors }) => {
+const DivisionByGroupFields = ({ intl }) => {
+  const { validDiscussionTopics } = useContext(LegacyConfigFormContext);
   const {
     handleChange,
     handleBlur,
@@ -104,8 +105,8 @@ const DivisionByGroupFields = ({ intl, discussionTopicErrors }) => {
                           onBlur={handleBlur}
                           defaultValue={divideDiscussionIds}
                         >
-                          {discussionTopics.map((topic, index) => (
-                            topic.name && !discussionTopicErrors[index] ? (
+                          {validDiscussionTopics.map((topic) => (
+                            topic.name ? (
                               <Form.Checkbox
                                 key={`checkbox-${topic.id}`}
                                 id={`checkbox-${topic.id}`}
@@ -135,7 +136,6 @@ const DivisionByGroupFields = ({ intl, discussionTopicErrors }) => {
 
 DivisionByGroupFields.propTypes = {
   intl: intlShape.isRequired,
-  discussionTopicErrors: PropTypes.arrayOf(PropTypes.bool).isRequired,
 };
 
 export default injectIntl(DivisionByGroupFields);
diff --git a/src/pages-and-resources/discussions/app-config-form/apps/shared/discussion-topics/DiscussionTopics.jsx b/src/pages-and-resources/discussions/app-config-form/apps/shared/discussion-topics/DiscussionTopics.jsx
index 973fd34e0..ef9cc6a15 100644
--- a/src/pages-and-resources/discussions/app-config-form/apps/shared/discussion-topics/DiscussionTopics.jsx
+++ b/src/pages-and-resources/discussions/app-config-form/apps/shared/discussion-topics/DiscussionTopics.jsx
@@ -1,24 +1,28 @@
-import React, { useEffect } from 'react';
+import React, { useEffect, useContext } from 'react';
 import { useDispatch } from 'react-redux';
 import { Add } from '@edx/paragon/icons';
 import { Button } from '@edx/paragon';
 import { injectIntl, intlShape } from '@edx/frontend-platform/i18n';
 import { FieldArray, useFormikContext } from 'formik';
 import { v4 as uuid } from 'uuid';
-import PropTypes from 'prop-types';
 
 import messages from '../messages';
 import TopicItem from './TopicItem';
 import { updateValidationStatus } from '../../../../data/slice';
+import { LegacyConfigFormContext } from '../../legacy/LegacyConfigFormProvider';
 
-const DiscussionTopics = ({ intl, discussionTopicErrors }) => {
+const DiscussionTopics = ({ intl }) => {
   const {
     values: appConfig,
-    setFieldValue,
     validateForm,
   } = useFormikContext();
-  const { discussionTopics, divideDiscussionIds } = appConfig;
+  const { discussionTopics } = appConfig;
   const dispatch = useDispatch();
+  const {
+    discussionTopicErrors,
+    validDiscussionTopics,
+    setValidDiscussionTopics,
+  } = useContext(LegacyConfigFormContext);
 
   const isFormInvalid = discussionTopicErrors.some((error) => error === true);
   useEffect(() => {
@@ -28,16 +32,13 @@ const DiscussionTopics = ({ intl, discussionTopicErrors }) => {
   const handleTopicDelete = async (topicIndex, topicId, remove) => {
     await remove(topicIndex);
     validateForm();
-    const updatedDividedDiscussionsIds = divideDiscussionIds.filter(
-      (id) => id !== topicId,
-    );
-    setFieldValue('divideDiscussionIds', updatedDividedDiscussionsIds);
+    const validTopics = validDiscussionTopics.filter(topic => topic.id !== topicId);
+    setValidDiscussionTopics(validTopics);
   };
 
   const addNewTopic = (push) => {
     const payload = { name: '', id: uuid() };
     push(payload);
-    setFieldValue('divideDiscussionIds', [...divideDiscussionIds, payload.id]);
   };
 
   return (
@@ -85,7 +86,6 @@ const DiscussionTopics = ({ intl, discussionTopicErrors }) => {
 
 DiscussionTopics.propTypes = {
   intl: intlShape.isRequired,
-  discussionTopicErrors: PropTypes.arrayOf(PropTypes.bool).isRequired,
 };
 
 export default injectIntl(DiscussionTopics);
diff --git a/src/pages-and-resources/discussions/app-config-form/apps/shared/discussion-topics/DiscussionTopics.test.jsx b/src/pages-and-resources/discussions/app-config-form/apps/shared/discussion-topics/DiscussionTopics.test.jsx
index 752d223cd..22368938e 100644
--- a/src/pages-and-resources/discussions/app-config-form/apps/shared/discussion-topics/DiscussionTopics.test.jsx
+++ b/src/pages-and-resources/discussions/app-config-form/apps/shared/discussion-topics/DiscussionTopics.test.jsx
@@ -20,6 +20,7 @@ import { getAppsUrl } from '../../../../data/api';
 import { fetchApps } from '../../../../data/thunks';
 import executeThunk from '../../../../../../utils';
 import { legacyApiResponse } from '../../../../factories/mockApiResponses';
+import LegacyConfigFormProvider from '../../legacy/LegacyConfigFormProvider';
 
 const appConfig = {
   id: 'legacy',
@@ -36,7 +37,15 @@ const appConfig = {
   blackoutDates: '[]',
 };
 
-const discussionTopicErrors = [false, false];
+const contextValue = {
+  validDiscussionTopics: [
+    { name: 'General', id: 'course' },
+    { name: 'Edx', id: '13f106c6-6735-4e84-b097-0456cff55960' },
+  ],
+  setValidDiscussionTopics: jest.fn(),
+  discussionTopicErrors: [false, false],
+};
+
 const courseId = 'course-v1:edX+TestX+Test_Course';
 
 describe('DiscussionTopics', () => {
@@ -66,9 +75,11 @@ describe('DiscussionTopics', () => {
     const wrapper = render(
       <AppProvider store={store}>
         <IntlProvider locale="en">
-          <Formik initialValues={data}>
-            <DiscussionTopics discussionTopicErrors={discussionTopicErrors} />
-          </Formik>
+          <LegacyConfigFormProvider value={contextValue}>
+            <Formik initialValues={data}>
+              <DiscussionTopics />
+            </Formik>
+          </LegacyConfigFormProvider>
         </IntlProvider>
       </AppProvider>,
     );
diff --git a/src/pages-and-resources/discussions/app-config-form/apps/shared/discussion-topics/TopicItem.jsx b/src/pages-and-resources/discussions/app-config-form/apps/shared/discussion-topics/TopicItem.jsx
index 8269a3d64..24830b7af 100644
--- a/src/pages-and-resources/discussions/app-config-form/apps/shared/discussion-topics/TopicItem.jsx
+++ b/src/pages-and-resources/discussions/app-config-form/apps/shared/discussion-topics/TopicItem.jsx
@@ -1,4 +1,4 @@
-import React, { useState } from 'react';
+import React, { useState, useContext, useEffect } from 'react';
 import { injectIntl, intlShape } from '@edx/frontend-platform/i18n';
 import {
   Button,
@@ -13,15 +13,46 @@ import { Delete, ExpandLess, ExpandMore } from '@edx/paragon/icons';
 import { useFormikContext } from 'formik';
 import PropTypes from 'prop-types';
 import messages from '../messages';
+import { LegacyConfigFormContext } from '../../legacy/LegacyConfigFormProvider';
+import uniqueItems from '../../../utils';
 
 const TopicItem = ({
   intl, index, name, onDelete, id, hasError,
 }) => {
-  const { handleChange, handleBlur, errors } = useFormikContext();
+  const {
+    handleChange, handleBlur, errors, values: appConfig, setFieldValue,
+  } = useFormikContext();
   const [inFocus, setInFocus] = useState(false);
   const [showDeletePopup, setShowDeletePopup] = useState(false);
   const [collapseIsOpen, setCollapseOpen] = useState();
   const isGeneralTopic = id === 'course';
+  const {
+    validDiscussionTopics,
+    setValidDiscussionTopics,
+  } = useContext(LegacyConfigFormContext);
+  const { discussionTopics, divideDiscussionIds } = appConfig;
+
+  /**
+ * Update valid discussion topics & divided discussion topics.
+ * Removes a specific topic from valid discussion topics & divided discussion topics
+ * if it is invalid.
+ * Adds a specific topic to valid discussion topics & divided discussion topics
+ * if it is invalid.
+ */
+  useEffect(() => {
+    if (hasError) {
+      const validTopicsIds = validDiscussionTopics.filter(topic => topic.id !== id);
+      setValidDiscussionTopics(validTopicsIds);
+      setFieldValue('divideDiscussionIds', divideDiscussionIds.filter(topic => topic.id !== id));
+    } else {
+      const validTopicsIds = uniqueItems(validDiscussionTopics.map(topic => topic.id), [id]);
+      const validTopics = discussionTopics.filter(
+        topic => validTopicsIds.includes(topic.id),
+      );
+      setValidDiscussionTopics(validTopics);
+      setFieldValue('divideDiscussionIds', uniqueItems(divideDiscussionIds, [id]));
+    }
+  }, [hasError, inFocus]);
 
   const getHeading = (isOpen = false) => {
     let heading;
diff --git a/src/pages-and-resources/discussions/app-config-form/utils.js b/src/pages-and-resources/discussions/app-config-form/utils.js
new file mode 100644
index 000000000..ceeee2f63
--- /dev/null
+++ b/src/pages-and-resources/discussions/app-config-form/utils.js
@@ -0,0 +1,6 @@
+/** Append items and makes sure the items are unique. */
+const uniqueItems = (sourceArray, items = []) => (
+  [...new Set([...sourceArray, ...items])]
+);
+
+export default uniqueItems;