Bug in room settings (restricted nicknames)

if I enable “Only login with registered nickname” in Room Settings is that still possible to take a random nickname and join the channel/room.

E.g.:

Registerd account nickname is "test"
Room have “Only login with registered nickname” enabled.

I can join with nickname “foobar” the channel.

I tested that on Openfire 3.8.2 and Openfire 3.7.1.