I've not heard of that problem before. I had a problem with one of my capsules and SP eventually replaced the capsules, but I don't believe it mattered if I rotated the upper part of the body.
My guess (and it's just a guess) is that a ground wire has come loose, and so now it's grounding down through the body instead, which is an intermittent ground when you rotate it. Definitely a job for Busman.