The only disconnector problem I'm aware of is the situation where the hook of the part doesn't fully engage the shoulder at the rear of the hammer and you get either slam fires when the impact of the bolt returning to battery jars the hammer off of the not fully engaged disconnestor, or hammer follow through, where the disconnector isn't engaging at all, and the hammer just follows the bolt carrier down and leaves you with a failure to fire, with the hammer down on a live round.
In the first instance, you can usually bring engagement back to spec by pulling the disconnector and lightly filling the flat surface on the bootom, in front of the pin hole. This will usually bring the position of the hook enough further forward to remedy the situation. In the second case, where the disconnector isn't holding the hammer back at all, you can try the filing technique, but the mismatch may be bad enough to require a new disconnector.
In either event, the solution is fairly simple, to a real pain in the butt problem. For what it's worth, I have seen some really poorly dimensioned aftermarket disconnectors in the past few years; that would give you this problem right from the start. That's why I started buying Govt contract Colt M16 disconnectors at the gun shows, and cutting the full auto tails off of them, to use in my ARs. Haven't had the problem ever since[:D]
(Edited to add) Just read your cast vs forged posting, in which you talked about the nature of the problem. Sounds like either an out of spec trigger, w/too narrow a slot , or an out of spec disconnector, which I think is more likely; especially given the parts brand you mention using. Me? I'd throw both parts out and get either Colt or Bushmaster pieces, but I guess that's your call[:D]