Quick question concerning my reverse light indicator

Yes ground is fastened using a star washer and sheet metal screw. just tried this, lossened the reverse light retainer and dropped the reverse light indicator down from the dash to where it was off in reverse, the radio still will **** off while putting it in reverse even with the reverse light indicator off, now its got me thinking, all this is happening with the ignition on only, meaning I haven't started the car and see if it does the same. Is it possible that the actual reverse lights on the back are causing a issue? I wont be able to start it until tomorrow night as it's pouring rain and cant open the garage. Im wondering if the turning on of the reverse lights on the back is causing the problem