It looks like a problem I had some time ago.
my level was going to run slower and slower.
There were two functions that caused the problem:
one that just looped, doing some instructions,
and another one, that looped too, and was calling the first.
So I got a function that every frame was calling another function which never ended.
This might be the problem, and not the lightm but I might be wrong.
Just a thought.