As reported also at https://bugzilla.redhat.com/show_bug.cgi?id=1900232 Seems a command like smbclient /server/share -U$user%$password -E -d 2 -c tarmode full -Tc tarfile.tar will create a dump with nested dir structure
see https://gitlab.com/samba-team/samba/-/merge_requests/1704 commit 31753815 introduced this issue which unfortunately is not spotted by CI because the tarmode tests are marked as flapping (Additionally the tar tests are also currently broken and again because they are marked as flapping we missed that too so you can't run the tests manually)
*** This bug has been marked as a duplicate of bug 14581 ***