Losing files on iCloud

I have a number of files that seem to have disappeared from iCloud. I initially couldn’t remember if I just moved them as I found some on OneDrive, however recently a Numbers document had vanished from my iCloud Drive and had to replace it (thankfully from a OneDrive backup) however I’ve just gone to edit the same file on iCloud only a week later and the file has disappeared from iCloud once again. I had last edited on my iPad and couldn’t see it anywhere. It wasn’t in recently deleted and wasn’t in the recovery option on iCloud website.

Can anyone help? Looking through my other iCloud documents I’ve noticed a few files missing while the folder structure all remains in place. It’s a good job most of my documents are stored on One Drive these days otherwise I may have lost more.