Hi All,
Currently, we haven't received any reports or service health issues about this behavior. Given this situation, we do understand the inconvenience caused and apologize for it.
This isn't quite true.
I reported it as an issue via service health and it returned as "no issue found" - when there is as demonstrated by several of us all reporting the same issue starting this week with no changes to lists.
I also have a ticket raised via support to investigate.
Unfortunately it seems it takes quite a lot of people to report an issue before it finally gets acknowledged as an issue...
This should have been flagged in service health from 10am yesterday when it was reported to Microsoft.