Resolution of blocking comments does not remove blocking disposition

In several (private repo, unfortunately) recent PRs where I have made a single blocking comment, clicking "Acknowledge" or otherwise changing my disposition in that discussion to Approving (in response to a fix) results in the right set of summary icons in the "discussions" column (none blocking), but the overall status of "Blocking & Discussing" remains. In github, I show as "requesting changes" but the requested-changes icon by my user links to the commit where the conversation started, which is now force-pushed into nonexistence.

Dismissing my review allows merge, but I've discovered that re-commenting in the original discussion with blocking disposition again, submitting that review, then re-clearing that disposition and submitting a final time also clears the general blocking disposition (and the requested change in github also goes away).

There are two candidates I can see for the cause:
1) In at least the most recent case, the file on which I commented was removed in the revision where I approved the change (and that was a force-push, removing the file from the commit set entirely). This might also apply to files that are simply reverted (which I think was the case during the previous times this happened).
2) Less likely (because squash-and-force-push is standard in our company and if this were the cause, many more people would have the issue): conversations started in commits that are force-pushed away don't update properly in github after the force push.