Folder disappears

I had something strange happen today
Started working on a scene, needed information on a character, so I clicked the + sign on the folder where I have some of the characters’ bios.
the folder refused to open
clicked it again. Nothing (the program was NOT frozen. I was able to work on the scene, and open other folders.)
I clicked the + sign few more times.
Nothing. then… the folder and all of its subfolders and text files suddenly DISAPPEARED

Not in the trash, so I did a search for the name of the folder (Louisiana) It brought up references from the research folder, and within the novel, but not folder itself

I then searched for the names of several of the characters. Those txt files showed up, but not the main Louisiana folder they were in originally, so I had no idea where they had moved to

Fortunately I do automatic back ups when I close, so I copied the new section I was working on to a txt file on the desktop. Closed, went into my HD renamed the corrupt project, opened the back up, renamed etc, so ALL is well. I did not lose anything

However, it is strange behavior, to say the least. The project is slightly over a Gig, but this is the only time this has occurred.
Scrivener DID NOT crash, I was not syncing to Dropbox or anything else. Can anyone explain this?
I hope I described this clearly, because I am mystified and need to know if I did something wrong :question:

PS-- the aforementioned folder had not gotten “grouped” with any other files either

It sounds to me as though there might have been an “uncaught exception”, which in programming terms is kind of like a very small crash in one part of the program. Usually, it will produce an error immediately and request you shut down the software, but in some conditions they can go silent and cause strange things to happen throughout the software. Since it hasn’t happened again, it’s probably not something easy to reproduce, but if you do see it happen, try and remember exactly what you were doing leading up to the event and see if you can trigger it again—then hopefully we can do the same thing and find the bug. Unfortunately these kinds of bugs can be very hard to track down though, because it could have been something you did half an hour prior that only just then became visible.

the only thing can add is that when the folder would not open, I kept clicking it.
Oh, and I do use an older Wacom tablet ( Graphire ET 0405-U) but don’t think that’s the issue as I’ve used it for a long time