This has happened on several occasions. I’m aware that Control Y adds video in instead of redo, so after screwing up a couple projects I’ve learned to avoid that, however I’ve been finding that Control Z sometimes does the same thing. If I press the undo key more than a few times in a row, even if I wait several seconds between each one, it seems to shuffle my video up and move video tracks around. Of course I save my videos often but this still sometimes loses me hours of progress. For example, just now I hit undo a few times and it moved my video so that what would normally be a few minutes in on the video track is now the start of the movie. The audio, however, is still in the original spot so its all out of sync. Trying to further press undo or redo only makes it worse.
Edit: The seemingly deleted first few minutes of the video track were just moved to the end of the track, so I was able to salvage my work, but it is still an issue that should be fixed.