Yes, my wife recently lost a bunch of files on her iPad. The files just dissapeared and are nowhere to be found. Of course I thought that it must have been a "user error", but some research showed that this a bug that affects a bunch of people [1][2] (might only affect files that you've written into with an apple pencil).

If apple can't even guarantee the users documents, I wonder what else might be wrong.

[1] https://discussions.apple.com/thread/255156283?sortBy=rank

[2] https://www.reddit.com/r/ipad/comments/19evmb8/files_disappe...