On the Marlin strat I've been trying to make worthwhile, there is an odd tuning issue. I've seen it before on other cheap or old guitars but I don't know what causes it.
Basically, if I tune the guitar properly, either by ear, or using a tuner, so all the strings are in tune, when I hit a power chord/chord one string always sounds wrong (B). It only sounds right if I tune it slightly flat.
I've set the intonation, that's fine. What would cause this annoying problem? Do I need a new nut?