Error when updating pager_heading in Views Module - "A valid cache entry key is required. Use getAll() to get all table data"

Quite a few sites have already taken that upgrade so there must be some more steps to reproduce. I think in HandlerBase:getEntityType, $this->getViewsData()->get($relationship['table']) is NULL for a given view configuration. Can you get the stack trace?

I am linking another issue that was uncovered by this update.

@cilefen, Here's the error message from the UI

Turns out I had a deprecated View - wish watchdog could have been more clear on the issue.

@xandermar how did you find the deprecated view? Im seeing the same issue trying to upgrade my environment to 10.3.6.

Seeing same issues here - I went through all Views and removed deprecated ones that were not functioning (or wsod) and reset any 'broken/missing handlers'. All working fine now.