I would bet your "tru nock" is causing some problems. I have seen it before. I had a couple of tuning issues in the last year and just recently discoverd they were both due to either brass nocks used for speed buttons and those tru ball spider/speed ball silencers. Constant nock high tears that would "move to tail left as the nock was adjusted. I can't say that's your problem, but I would take a look at those items, provided you really have tried everything else.