Wow a bug! got into a room that had an extra mini boss that was inside another mini boss so I got owned. I don't really know what causes it so it might be hard to fix.
I actually saw the same thing, only there was 1 pair of lazers that wasn't moving at all and actually stayed even after killing a miniboss. I wish that i didn't forget to screenshot that one. Forgot to mention that i saw this happening in on 4.0. So far, i haven't seen that happen to me on 5.0