Folders that cannot be deleted

A very strange situation is occurring.
Folders shared by other user are treated as PDF file or Picture file. The user cannot unshare this folder due to an error. Also, the user cannot delete it. The folder remains in the file list even if the sharing source user unshares it.

Is there a way to forcibly remove this strangely shared folder?

NC19.0.4, PHP 7.4.12, CentoOS 7.7, Nginx 1.18.0

I was able to solve it myself. The solution was to delete the group and recreate it.