The root cause for the issues during upgrades appear to be the same. This has me thinking about how can the system around upgrades be improved. Sorry, this is just a natural habit from doing dozens of RCAs at work.
Are there a lot of other plugins in the app.yml? If the list is small, it may be worth vetting them before doing the upgrade. I’m not exactly sure what that process looks like, but happy to try and figure it out. It might be as simple as asking GeePeeTee to evaluate the list and compare it to the upgrade version. A little upfront there may save you a headache in debugging.
Thanks for keeping the site going.