Quoted from Brootull:
So the previous owner installed LED’s and some of the bulbs, particularly the lights on the vault, are always lit whether they are supposed to be on or not. It’s rather faint but they are on nonetheless. Anyone know the cause and is there a fix?
It's called ghosting. I have the same issue happening on a TAF I just got in. I'm curious what rom version you're running? For the record every machine I've put LEDs in I've installed GIOCD and LEDOCD boards. I suspect this one will also get them.