If the dimmer light is just cosmetic and it doesn't affect performance then the short answer is it probably needs to go back to Bryston and they will replace the offending part. I had this problem with a 4Bsst and Bryston fixed it but I can't remember the part they replaced. I know my dealer which has a very good service department couldn't figure it out.
My recollection is it will never affect the performance of the amp, but it drove me nuts so I got it fixed. Fortunately my amp was under warranty.
Not sure on the paint.
Good listening,
Mike