On my Les Paul, the intonation on the "A" string is correct, but the saddle is too far forward than what would be considered "normal". I took it to a repair shop and they couldn't find anything extraordinarily wrong with the nut, bridge, saddle cuts, etc. I'm using normal, gauged sets of strings from several different manufacturers. The guitar plays in tune up and down the neck. There's a very slight bow in the neck... nothing serious. All the other strings are ok. I'm stumped. What could cause this?