Pass Inteference Call

Sorry if a thread has already been started, but that P.I. call in the end zone that was picked up b/c Drew was outside of the pocket, what the heck was up with that. My friend and I who watch alot of football were both baffled at the call. The NFL now has so many rules maybe this one went un-noticed to us. Any clarification on this rule would be nice

Not sure, but the WR was defenitly interfered with beyond 5 yards...I was scratching my head on that one too.