Unusual lens problem

Yesterday my 100mm WR DFA Macro lens started behaving oddly. The autofocus was jerky and inaccurate. The back button I use for autofocus seemed to fire the shutter or at least flip the mirror! The exposure readings were flashing in the screen. Then it would fire the shutter after a few seconds without touching it. I tried removing, cleaning contacts etc and it would fire once normally then revert to fault thereafter. One time I couldn't turn it off. It was like a ghost in the works. The K30 worked fine with all the other lenses. So I tried it on my friend's K5 and it was fine. A real strange one. Trying to think what could have changed I thought it might have been the first time I used it since calibrating my lenses. The lens was set on +7. I reset it to 0 and low and behold it started working normally. I then changed it to +5 and still ok. Haven't risked going back to +7.
The calibration didn't effect any other lenses.
Seems impossible to me - I guess the change must have corrupted something in the software, although you would have thought that switching on and off would have reset it.
Most odd, thought I'd report it just in case something similar happens to someone else.
Dave

I don't think the calibration would cause this Dave, although I can't dispute your findings so far. I've calibrated all my lenses on the K-5 and K-5IIs with no strange symptoms. It sounds more like an electrical issue to me; if it's behaving correctly now I would be tempted to re-do the calibration and try it again. You can always revert back if it causes a problem.

Regards
David

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That's what I've done David and it's fine. I agree it doesn't make much sense as all the other lenses worked fine after calibration. It must have been a software glitch somewhere that only affected that lens, Most odd, I'll just have to wait and see if it happens again.

I had a similar experience about a week ago when I tried to take some shots with my K5II + Sigma 150-500mm.

AF was all over the place, it would seem to focus OK, then shift the lens a little more making the image in the VF very OOF.

The remedy was to remove it and clean the electrical contacts on the lens and the camera body.

After re-fitting lens to camera, all was fine again and has been ever since.