Ah, ok. No, there is nothing to find. vsdnew/xxxxxx is mounted under vsdnew and if I mount vsdnew/xxxxxx elsswhere, nothing exists in the /home/vsdnew/xxxxxx path.
The interesting point in my view is that zdb is already suspecting a leak with all these ~70.0000 files: "path not found, possibly leaked". Running a full "zdb -e POOL" is not showing any leaks. It just tells me, everything is fine...
If I investigate deeper an look at the parent object, it's often a 'normal' and existing path - like a mail user home. So, the (not existing) object is pointing to a file that was probably deleted (mail cur directory). I assume there is a bug in zfs. And I assume it happens in combination with rotating snapshots (which we have on all the servers which such effects): a daily snapshot is created, and any snapshots older e.g. 7 days are deleted.
But I can't proof it.