Michael, thanks for summarizing the potential fixes. I had already tried #1 and #2 would take some time, but it appears that #3 fixed the problem for me. At least the first few gmail messages are behaving properly (e.g. moving out of inbox). I am hopeful that this is the fix and will report back here.
@Michael_Tsai I can confirm that the fix from yesterday is indeed a fix, everything is working as expected again. Thank you for your great support on this!
Great, thank you so much for confirming.