Non

Here's one more data point on the behavior of this strange problem, which we're also encountering on our hub with students. I made some changes to a version-controlled notebook, nb2.ipynb, that I then discarded by doing a git restore nb2.ipynb at the terminal after having closed the file. When I reopened it, it showed up blank. Since I have learned that renaming it helps recover, I did the following:

After 2, the following very strange thing occurred: the tab where it was opened all of a sudden flipped back to showing f.ipynb on it, despite the notebook now being called nb2. If I hover, I see that name, but the tab reads f, as shown here:

There's some strange inconsistency occurring internally, that is manifested by this behavior. It doesn't help much, but I figured right now every bit might provide a clue to how to ultimately fix this very problematic issue (which is really making RTC borderline unusable).