On MacOS, files may have extended attributes attached. These attributes are copied together with the files. To prevent issues during further processing, the extended attributes of the copies must be removed. This action was implemented as solution of an older bug.

The solution is incomplete because it does not handle files with read-only permissions correctly. Without write permission, xattr cannot remove the extended attributes. The action is rejected with a "permission denied" error.

The issue is present in all releases. I reproduced it in 11, 17, ... 23, head