subfolder with XPT files causes "Permission denied" error

[JozefAerts]

An FDA requirement is that "splitted datasets" (the term is essentially wrong, as these usually are not a result of splitting, but have been created separately) should go into the subfolder "split". When we do so, e.g. using the files from the CDISC "Metadata Submission Guidelines 2.0", the validator throws an error "PermissionError: [Errno 13] Permission denied:" (see screenshot).
But maybe there is just something wrong with my folder permissions?

Version used is "develop" on 2023-03-11.