Hello,
Since the migration from Maple to Nutmeg, the contents with an emoji in the title of the subsection cause a crash in the logs and prevent the course outline from being displayed.
On a new installation the problem remains.
When creating a new course, the problem does not appear. But when exporting the same course, its import causes an error.
I tried to convert the mysql database to utf8mb4 but the error still persists.
Example of creating a test course with and without emoji:
![image|690x383]https://discuss.overhang.io/uploads/default/original/2X/2/21f9dd6e14aa7f06a69b8411967bb46dd9e50fb4.png)
Course Outline does not display the content of the sections:
(as a new user I am only allowed to upload one media, so I’m going to upload the other screenshots elsewhere
EDIT: It seems that this is impossible, as a new user I am limited to 2 links per post. Sorry about that. 
)
What happens after clicking on “start course”:
CMS Logs:
cms-worker_1 | [2022-07-18 16:44:09,819: ERROR/ForkPoolWorker-8] Task openedx.core.djangoapps.bookmarks.tasks.update_xblocks_cache[54a02550-46e0-48a2-b4ef-0f576eee5c49] raised unexpected: OperationalError(1366, "Incorrect string value: '\\xF0\\x9F\\x93\\xBA S...' for column 'display_name' at row 1")
cms-worker_1 | Traceback (most recent call last):
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/django/db/models/query.py", line 581, in get_or_create
cms-worker_1 | return self.get(**kwargs), False
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/django/db/models/query.py", line 435, in get
cms-worker_1 | raise self.model.DoesNotExist(
cms-worker_1 | openedx.core.djangoapps.bookmarks.models.XBlockCache.DoesNotExist: XBlockCache matching query does not exist.
cms-worker_1 |
cms-worker_1 | During handling of the above exception, another exception occurred:
cms-worker_1 |
cms-worker_1 | Traceback (most recent call last):
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/django/db/backends/utils.py", line 84, in _execute
cms-worker_1 | return self.cursor.execute(sql, params)
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/django/db/backends/mysql/base.py", line 73, in execute
cms-worker_1 | return self.cursor.execute(query, args)
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/MySQLdb/cursors.py", line 206, in execute
cms-worker_1 | res = self._query(query)
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/MySQLdb/cursors.py", line 319, in _query
cms-worker_1 | db.query(q)
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/MySQLdb/connections.py", line 254, in query
cms-worker_1 | _mysql.connection.query(self, query)
cms-worker_1 | MySQLdb._exceptions.OperationalError: (1366, "Incorrect string value: '\\xF0\\x9F\\x93\\xBA S...' for column 'display_name' at row 1")
cms-worker_1 |
cms-worker_1 | The above exception was the direct cause of the following exception:
cms-worker_1 |
cms-worker_1 | Traceback (most recent call last):
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/celery/app/trace.py", line 451, in trace_task
cms-worker_1 | R = retval = fun(*args, **kwargs)
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/celery/app/trace.py", line 734, in __protected_call__
cms-worker_1 | return self.run(*args, **kwargs)
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/edx_django_utils/monitoring/internal/code_owner/utils.py", line 193, in new_function
cms-worker_1 | return wrapped_function(*args, **kwargs)
cms-worker_1 | File "/openedx/edx-platform/openedx/core/djangoapps/bookmarks/tasks.py", line 163, in update_xblocks_cache
cms-worker_1 | _update_xblocks_cache(course_key)
cms-worker_1 | File "/openedx/edx-platform/openedx/core/djangoapps/bookmarks/tasks.py", line 137, in _update_xblocks_cache
cms-worker_1 | block_cache, created = XBlockCache.objects.get_or_create(usage_key=block_data['usage_key'], defaults={
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/django/db/models/manager.py", line 85, in manager_method
cms-worker_1 | return getattr(self.get_queryset(), name)(*args, **kwargs)
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/django/db/models/query.py", line 588, in get_or_create
cms-worker_1 | return self.create(**params), True
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/django/db/models/query.py", line 453, in create
cms-worker_1 | obj.save(force_insert=True, using=self.db)
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/model_utils/models.py", line 38, in save
cms-worker_1 | super().save(*args, **kwargs)
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/django/db/models/base.py", line 739, in save
cms-worker_1 | self.save_base(using=using, force_insert=force_insert,
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/django/db/models/base.py", line 776, in save_base
cms-worker_1 | updated = self._save_table(
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/django/db/models/base.py", line 881, in _save_table
cms-worker_1 | results = self._do_insert(cls._base_manager, using, fields, returning_fields, raw)
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/django/db/models/base.py", line 919, in _do_insert
cms-worker_1 | return manager._insert(
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/django/db/models/manager.py", line 85, in manager_method
cms-worker_1 | return getattr(self.get_queryset(), name)(*args, **kwargs)
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/django/db/models/query.py", line 1270, in _insert
cms-worker_1 | return query.get_compiler(using=using).execute_sql(returning_fields)
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/django/db/models/sql/compiler.py", line 1416, in execute_sql
cms-worker_1 | cursor.execute(sql, params)
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/django/db/backends/utils.py", line 66, in execute
cms-worker_1 | return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/django/db/backends/utils.py", line 75, in _execute_with_wrappers
cms-worker_1 | return executor(sql, params, many, context)
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/django/db/backends/utils.py", line 84, in _execute
cms-worker_1 | return self.cursor.execute(sql, params)
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/django/db/utils.py", line 90, in __exit__
cms-worker_1 | raise dj_exc_value.with_traceback(traceback) from exc_value
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/django/db/backends/utils.py", line 84, in _execute
cms-worker_1 | return self.cursor.execute(sql, params)
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/django/db/backends/mysql/base.py", line 73, in execute
cms-worker_1 | return self.cursor.execute(query, args)
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/MySQLdb/cursors.py", line 206, in execute
cms-worker_1 | res = self._query(query)
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/MySQLdb/cursors.py", line 319, in _query
cms-worker_1 | db.query(q)
cms-worker_1 | File "/openedx/venv/lib/python3.8/site-packages/MySQLdb/connections.py", line 254, in query
cms-worker_1 | _mysql.connection.query(self, query)
cms-worker_1 | django.db.utils.OperationalError: (1366, "Incorrect string value: '\\xF0\\x9F\\x93\\xBA S...' for column 'display_name' at row 1")
LMS Logs on course outline page:
caddy_1 | {"level":"error","ts":1658162672.7590897,"logger":"http.log.access.log0","msg":"handled request","request":{"remote_addr":"172.18.0.1:49142","proto":"HTTP/1.0","method":"GET","host":"lms.localhost.fr","uri":"/api/edx_proctoring/v1/user_onboarding/status?is_learning_mfe=true&course_id=course-v1%3ATEST%2BTEST%2BTEST&username=usertest"},"user_id":"","duration":0.048045005,"size":83,"status":404}
Course backup example : hxxps://transfer.sh/8HPa1U/course.emoji_test.tar.gz
Do you have any clues?
I remain available for testing.
Thanks 
