9/8/2022: 2:00 PM
A hotfix for this issue has been pushed out to sites at this time, the issue has been resolved.
9/6/2022: 9:00 AM
Our team is aware of an issue where Important Announcement messages are no longer displaying in the Messages list within the Messages module. The Important Announcement messages still exist, but are hidden from view.
We are actively working on a fix for all sites. If there is a time sensitive need for a fix on your site, please submit a Support ticket for assistance.