Did it do this with the original lens? Also, check for the wire connections to the lens and PC board. If all else fails it probably needs the lens to be adjusted. I would do this as the last resort since it is a bit annoying and you need to be careful with the wires on the plugs to it. There is one screw on the bottom of the lens that is adjustable, try turning it clockwise a little at a time when testing out a disc. If that all doesn't work you may need another HOP-M3 possibly, since some can be not so great out of the factory. This is why I ordered 2 of them at once and for longer life out of my Duo if both work fine.