It's not UTC time, it's whatever the local settings are set to (New York in prod)

lms/templates/courseware/submission_history.html

@@ -4,7 +4,7 @@
 % for i, entry in enumerate(history_entries):
 <hr/>
 <div>
-<b>#${len(history_entries) - i}</b>: ${entry.created} UTC</br>
+<b>#${len(history_entries) - i}</b>: ${entry.created} (${TIME_ZONE} time)</br>
 Score: ${entry.grade} / ${entry.max_grade}
 <pre>
 ${json.dumps(json.loads(entry.state), indent=2, sort_keys=True) | h}