Thanks for your post -- I appreciate the information you've provided. In order for our engineers to be able to fix a potential bug, we have to be able to reproduce the issue so that we can take a closer look and identify what's causing it. Generally, with a Docs-wide bug, I'm able to easily reproduce the issue when working in any document. Since I'm not able to reproduce this with my own revision history (and since I have not seen other recent reports of this from other users), it's difficult to pin down where the problem is happening and try to work towards a solution
By no means am I ruling out that there might be a bug here -- unfortunately, there's just not much we can do about it on our end until we're able to reproduce it to investigate further. Are you seeing the same issue in any of your other documents' revision histories?