Lights bug when playing Elevator Action Returns at 50hz, can someone confirm?

I was playing Elevator Action Returns on my unmodified PAL Saturn using a Saroo and noticed a bug at the start of the first stage. When I shoot the lights the wrong floor goes dark. It affects the floor above the one that should be affected.

Is this because the game is running at 50hz? I've ordered a Saturn from Japan but it's coming via surface mail so it'll be a while and I just want to rule out the Saroo.