Deleted SharePoint folders keep reappearing

Hi.

No - it's not a teams site. Just a plain old no-frills site used for file sharing. So there are no channels involved. The site has no plugins, apps or automation - it's just an out-of-the-box site connected to each user's OneDrive using the "Add shortcut to oneDrive" feature.

Sadly, our security policies wont allow me to screenshot our business folders - for obvious reasons.

But, using dummy names: I can explain how it looks. In our site's Documents root folder, we might have a "Folder1" and "Folder2", each with a selection of subfolders (and some have files, others not).

When we delete "Folder1", then it re-appears (complete with it's subfolders), and SharePoint's "Created By" gives the name of another member of staff. Other copies like "Folder1-Fred", "Folder1-LAPTOP1" are also in the habit of just appearing (and again: each one is being created by different staff members). The re-created directory tress are usually empty of files (just the directories get created) although in some cases a small number of the original files also reappear.

This is NOT the result of clicking "restore" in the recycle bin, by the way - the directory is still in there.