diff --git a/openedx/core/djangoapps/xblock/runtime/blockstore_field_data.py b/openedx/core/djangoapps/xblock/runtime/blockstore_field_data.py
index d849bfcfb9..517e93b3e2 100644
--- a/openedx/core/djangoapps/xblock/runtime/blockstore_field_data.py
+++ b/openedx/core/djangoapps/xblock/runtime/blockstore_field_data.py
@@ -180,7 +180,9 @@ class BlockstoreFieldData(FieldData):
             # Otherwise, this is an anomalous get() before the XML was fully loaded:
             # This could happen if an XBlock's parse_xml() method tried to read a field before setting it,
             # if an XBlock read field data in its constructor (forbidden), or if an XBlock was loaded via
-            # some means other than runtime.get_block()
+            # some means other than runtime.get_block(). One way this can happen is if you log/print an XBlock during
+            # XML parsing, because ScopedStorageMixin.__repr__ will try to print all field values, and any fields which
+            # aren't mentioned in the XML (which are left at their default) will be "not loaded yet."
             log.exception(
                 "XBlock %s tried to read from field data (%s) that wasn't loaded from Blockstore!",
                 block.scope_ids.usage_id, name,
diff --git a/openedx/core/djangoapps/xblock/runtime/blockstore_runtime.py b/openedx/core/djangoapps/xblock/runtime/blockstore_runtime.py
index 8b3558bced..2f474ebdd2 100644
--- a/openedx/core/djangoapps/xblock/runtime/blockstore_runtime.py
+++ b/openedx/core/djangoapps/xblock/runtime/blockstore_runtime.py
@@ -13,7 +13,7 @@ from xblock.fields import ScopeIds
 
 from openedx.core.djangoapps.xblock.learning_context.manager import get_learning_context_impl
 from openedx.core.djangoapps.xblock.runtime.runtime import XBlockRuntime
-from openedx.core.djangoapps.xblock.runtime.olx_parsing import parse_xblock_include
+from openedx.core.djangoapps.xblock.runtime.olx_parsing import parse_xblock_include, BundleFormatException
 from openedx.core.djangoapps.xblock.runtime.serializer import serialize_xblock
 from openedx.core.djangolib.blockstore_cache import (
     BundleCache,
@@ -85,7 +85,12 @@ class BlockstoreXBlockRuntime(XBlockRuntime):
         This runtime API should normally be used via
         runtime.get_block() -> block.parse_xml() -> runtime.add_node_as_child
         """
-        parsed_include = parse_xblock_include(node)
+        try:
+            parsed_include = parse_xblock_include(node)
+        except BundleFormatException:
+            # We need to log the XBlock ID or this will be hard to debug
+            log.error("BundleFormatException when parsing XBlock %s", block.scope_ids.usage_id)
+            raise  # Also log details and stack trace
         self.add_child_include(block, parsed_include)
 
     def add_child_include(self, block, parsed_include):
diff --git a/openedx/core/djangoapps/xblock/runtime/olx_parsing.py b/openedx/core/djangoapps/xblock/runtime/olx_parsing.py
index e4a27e996b..9318cf415a 100644
--- a/openedx/core/djangoapps/xblock/runtime/olx_parsing.py
+++ b/openedx/core/djangoapps/xblock/runtime/olx_parsing.py
@@ -27,6 +27,9 @@ def parse_xblock_include(include_node):
     # An XBlock include looks like:
     # <xblock-include source="link_id" definition="block_type/definition_id" usage="alias" />
     # Where "source" and "usage" are optional.
+    if include_node.tag != 'xblock-include':
+        # xss-lint: disable=python-wrap-html
+        raise BundleFormatException("Expected an <xblock-include /> XML node, but got <{}>".format(include_node.tag))
     try:
         definition_path = include_node.attrib['definition']
     except KeyError:
diff --git a/openedx/core/djangolib/blockstore_cache.py b/openedx/core/djangolib/blockstore_cache.py
index c1d12d99c3..040bc6a127 100644
--- a/openedx/core/djangolib/blockstore_cache.py
+++ b/openedx/core/djangolib/blockstore_cache.py
@@ -202,8 +202,16 @@ def get_bundle_file_data_with_cache(bundle_uuid, path, bundle_version=None, draf
     cached list of files in each bundle if available.
     """
     file_info = get_bundle_file_metadata_with_cache(bundle_uuid, path, bundle_version, draft_name)
-    with requests.get(file_info.url, stream=True) as r:
-        return r.content
+    response = requests.get(file_info.url)
+    if response.status_code != 200:
+        try:
+            error_response = response.content.decode('utf-8')[:500]
+        except UnicodeDecodeError:
+            error_response = '(error details unavailable - response was not a [unicode] string)'
+        raise blockstore_api.BundleStorageError(
+            "Unexpected error trying to read {} from bundle {}: \n{}".format(path, bundle_uuid, error_response)
+        )
+    return response.content
 
 
 @lru_cache(maxsize=200)
diff --git a/openedx/core/lib/blockstore_api/__init__.py b/openedx/core/lib/blockstore_api/__init__.py
index 288aeada6c..8b6de205c6 100644
--- a/openedx/core/lib/blockstore_api/__init__.py
+++ b/openedx/core/lib/blockstore_api/__init__.py
@@ -51,4 +51,5 @@ from .exceptions import (
     BundleNotFound,
     DraftNotFound,
     BundleFileNotFound,
+    BundleStorageError,
 )
diff --git a/openedx/core/lib/blockstore_api/exceptions.py b/openedx/core/lib/blockstore_api/exceptions.py
index 06e6de93c6..b58251d31f 100644
--- a/openedx/core/lib/blockstore_api/exceptions.py
+++ b/openedx/core/lib/blockstore_api/exceptions.py
@@ -25,3 +25,7 @@ class DraftNotFound(NotFound):
 
 class BundleFileNotFound(NotFound):
     pass
+
+
+class BundleStorageError(BlockstoreException):
+    pass