One user has read permissions issues, unable to open specific files, seemingly random

One W10H22 user using integrated desktop agent is unable to open specific files.

For example they can open 9 out of 10 files in a specific folder, but all files have the same permissions and none have locks on them. The file that will not open generates the error -

“Sorry, we couldn’t find C:\user\app\filename. Is it possible it was moved renamed or deleted?”

The file itself still exists in place and can be accessed from other computers. It can even be accessed via the same machine remotely using an administrative share. The same issue occurs seemingly randomly to other files with the same user. The user can download problem files and open them locally, but cannot open directly out of the file explorer. Re-syncing the client does not help.

I am unable to determine a cause or solution. Any suggestions are appreciated.