First, it is probably a fairly serious problem, when the stylus loses contact with the groove wear is accelerated on both the cartridge and record. You say that it is not anti-skate, but have you put a twist in the wire from the tonearm to achieve anti-skate, and if so, how have you measured that the amount is correct? This is the trickiest arm to get anti-skate correct on, as it is so Mickey Mouse. I recently set-up a Dynavector XX-2 on a Super Scoutmaster and really had to monkey around until I got the anti-skate just right. Remember, if it is not correct, there is more force exerted on one wall of the groove than the other and side with less force will experience compromised tracking. My only other thought is are you measuring the tracking force in the plane of the record? Most scales require this, the exception is the, rather crude Shure balance, which is designed to work on top of the playing surface. And it could be bad pressings, but usually these make noise, but not buzzing, which would seem to indicate that the stylus is loseing groove contact. Are these the highly-modulated high-frequency passages that are problems?