I've been there, but fortunately, we both had the same call. I'm C, dribbler runs over defender on my block. I come up with a PC and close down (not enough). I see L start to (I think) transition down court. The long switch in 3 person was new to me then, so I was only slightly confused by this.
I turn, report my foul, and go back to administer the throw-in.
What I didn't know, was L was not transitioning for the switch, he was going around the backside of the players (I was table side) to report his foul and then took his proper position as new C, opposite table.
At the quarter break, the T comes up to us and asks if we realize we'd both reported the same foul.