On Tue, 16 Mar 2021 07:41:42 -0700
Marc Shapiro via Dng <dng@???> wrote:
> ...
> tmpfs 2466616 24 2466592 1% /run/user/1001
> tmpfs 2466616 24 2466592 1% /run/user/1002
> tmpfs 2466616 32 2466584 1% /run/user/1000

Is it possible that one of the users runs some program that holds
on to cached directory entries for the file(s) if not the files
themselves?

I believe there's currently significant effort going into trying to
isolate users, including root, from each other so that even sharing of
common resources is "hidden" (with virtual file systems and various
forms of "unsharing" and whatnot).

Ralph.