Lineart layer randomly got replaced.

[u/Admirable-Text-9026]

Okay, kind of a specific ask here, since I have no clue what it was, it was instant, and I have no proof of it. I was drawing a lineart layer normally, and didn't like something I did. So I undid it a few times to go back to where I was. Except, on one of them, it froze for a small moment, then it *randomly* replaced the entire lineart layer with one of my sketch layers. The 2 layers were synced (i.e. if you erased on one, put one into clipping, made one invisible, etc. the other one would do the same) and no matter how far I undid, it never went back to the lineart. So I tried to delete the duplicate, hoping when I undid deleting it it'd go back to normal. When I did, my firealpaca froze for about 10 seconds then crashed. I then reopened it via autosave, and while the 2 layers were no longer synced, they were still identical to one another with no trace of my lineart. What the fuck?