Files disappearing if I add notes with apple pencil

I notice hundreds of users have the same issue with ipad Files disappearing. Sometimes they are still visible under ‚Recents‘ but they are not accessible. They are also not deleted and cannot be moved or retrieved. Others have commented that perhaps a particular update is the culprit. However, I have had the same issue for well over a year. The one common factor with me is that only files which I have added handwritten notes to using apple pencil disappear. If apple tech support is unable to resolve this issue then it should be made clear to users that important documents cannot be reliably stored. In my case the world has not gone under because I use a third party back up. It’s a real pity. I love my ipad and its functionality but it is no longer a reliable work tool. If anyone has a suggestion I would be grateful.