Making a call in your partners area.

My regular partner recently worked a F/JV doubleheader with a different official. The conference assignor and an evaluator were present to rate the Varsity crew, but they also watched the JV game. The only major issue the evaluator had was that my partner made a foul call on a play in the other officials area of responsibility. Here is the play:

My partner was trail on a fast break by Team A, just as A1 jumped for a lay-up attempt, B1 grabbed his jersey from behind. The other official had no angle and was completely blocked out by A1. My partner made the call. Neither coach had an issue with the call or the fact that my partner made it.

After the game, the evaluator said that an official should never make a call outside their area of responsibility. Do the veteran officials agree? I understand the importance of watching the play in your area and not tracking the ball, but there are some situations where you see something obvious outside your area. Don't we have an obligation to call a foul/violation if we see it? Just wondering what others think.