This is fine for groups you prebuild before going into the dungeons, and it's agreed you'll be doing a hybrid/nontraditional role as that job. Since you bypass the role checks in the duty finder with a premade, this is fine the way it is.

Too much room for abuse, and too easy for arguments to break out if people queue as something other than their job's "acceptable" role.

I definitely think that they intended for people to have the capability for doing a hybrid build, but using the random group finder doesn't mesh well with that. Just build a team beforehand and have at it.