Sorry to hear about your issue. I also own the Proteus, which surely is a great cartridge. To be honest this doesn't really sound like a cartridge problem. I'm also pretty sure it has nothing to do with anti-skating, azimuth ot other alignment related issues.
So I guess you should try to be as methodical as possible. First you might consider trying the Proteus in a different system. I suspect this will rule out the cartridge as the culprit. Your description more likely suggests a cable issue. A loose contact perhaps, either with the tonearm inside cabling or the tonearm cable to the phono amp.
So I guess you should try to be as methodical as possible. First you might consider trying the Proteus in a different system. I suspect this will rule out the cartridge as the culprit. Your description more likely suggests a cable issue. A loose contact perhaps, either with the tonearm inside cabling or the tonearm cable to the phono amp.