Trigger, Collision, transform.position.y not registering on other player's machine


I have to be missing something completely obvious here, but I'm stumped.

I have a game where things need to be reset if an object (let's say obj1) falls below a certain y coordinate.

The game is very simple... two players take turns hitting obj1, it bounces around, and eventually drops off the plane, at which point it should be the next person's turn.

Originally I set up a "kill plane", recorded what obj1 last touched, and reset the scene based on the OnCollisionEnter feedback, but I was getting WILDLY inconsistent results. I put in some debugging code and noticed that the collision was only registering 30% of the time if it was player 2's turn. Okay, I thought. I'll make the collider a trigger and see if I can grab it there. That result was worse. It recorded the proper information every time it was player 1's turn, but only about 20% of the time if it was player 2's turn.

So then I thought I'd just use the Update function to see if obj1's y position had fallen below the kill plane y position. AGAIN, it only "sees" that obj1 has dropped below my set y position if it's player 2.

What is going on here? My entire game depends on accurately monitoring and recording object positions and collisions. Why is Photon not registering these events for one half of my players (only two in a room at a time)?