Originally Posted by
Pilot DAR
More or less what Jan99 has said, it's a wiring issue with that plane. To confirm, try a different headset in that position of that plane, and try your headset in a different plane. That said, that owner of the plane won't be rushing to correct the situation, it's not really a defect, and it could be quite a bit of work.
Tried my headset in two A/C to have the same problem, albeit one mid-flight. Reluctant to send it off (headset) given its had a recent service.