Backcourt AGAIN

I know... I know... why is this coming up again? (I searched & couldn't find this particular sitch)

A2 (in the frontcourt) passes the ball to A3, B2 deflects the pass towards the backcourt. Just before the ball strikes the floor in the backcourt A2 recovers the ball standing in the backcourt... violation, right??

Had A1 let the ball go into the backcourt by striking the floor first, then the defense caused the ball to go into the backcourt thus no violation, right??

I felt like I was the only one in the gym who had a clue... my "partner" even sided with the very knowledgable coach & fans because he saw the tip too.
Of course this was our 1st of 4 games together yesterday & I never could find the proof to defend that call.

Rules references & casebook play please.