There is a strong issue, for the Uchiha Clan. First, when activating Mangekyou. It does not state that you are initiating Mangekyou. This is the minor problem. The real issue, involves when Uchiha's attempt to use abilities that require Mangekyou, they simply do not work. If it is activated or not. This is a 24/7 issue, nothing has been done in order to cause this problem.
I'll take a look at that once I get the chance.