u/JustHereForShips21

Me and my friend were doing a head to head campaign and he, as a vassal, declared war on myself and other factions.

The reason I think it is a bug is because through the normal diplomatic screen vassals cannot declare war. Yet he found a work around where he just right clicked the armies and declared war and got his overlord to join in.

I have never seen this before in any Total War game. Is this a bug or overlooked feature?