Our fix has been deployed for several days and no other issues have arisen, so we are resolving this issue.
We believe that we resolved the issue by reverting a change which had switched the provider we use for feature flags. We will continue to investigate why this change resulted in the platform slowness.
The platform is experiencing general slowness, particularly with DD grading and moderation. Students and instructors are reporting that they are not able to log in or access their communities. The issue is currently being investigated.