"This check failed" for scheduled workflows across multiple repos

Since early morning on 7/29/2021, scheduled workflows across several of my projects have been failing with one or more jobs showing “This check failed”. Examples:

I don’t see any commonalities between the failing jobs. Some runs-on: ubuntu-latest, some runs-on: windows-latest.

“Re-Run All Jobs” has been successful the few times I’ve tried.

Any idea what’s going on? Any suggestions for things I can do to investigate or avoid the issue?