Hello,
Yes, that's what I thought at first.
In the web interface, when I assigned the "TOTO" directory as "main directory" to Peter, Truenas did not throw me out. He should have warned me that this dataset already had an owner.
Or, he de-assigned Paul's "TOTO" to Peter's profile record. But when I went to Paul's profile, "TOTO" was still assigned as Paul's "main directory".
I have not yet gone to see (in command line) who was the real owner of the "TOTO" dataset.
But in the web interface, there should be an "alert", because visually in their respective profiles, peter and paul are both owners of "TOTO".