I had the same problem. The metal around the screws holding your door latch falls apart. This causes the latch to bounce and light to flicker. You can put some washers on the three bolts holding the latch on, or if like mine it's past that drill two holes in some thin sheet metal and bolt it on like a big washer. That's what I did but I also put two self tapping screws in the bottom of my home made peice. Mine has been fine fir three weeks now.
To clarify... The " latch" I was talking about is on the inside if the door. You can only see it when the door us open. Hope this helps.