I had one do that, Paul at PDMNet said it was a hardware problem and apparently somewhat common, I sent it in and they fixed it. It was a pretty old SM and I thought it was just crud or water in the jack or on the PCB but I cleaned it up really good with alcohol with no success.
From: Steve D via Af Sent: Wednesday, November 12, 2014 9:02 PM To: af Subject: [AFMUG] Phantom Default Plug? I know I've seen this before, but just had an FSK 2.4 SM do this to me - real bugger too because it was the last in my truck while I was out doing a site test. Any ideas what caused it or how to fix it? I think I was in the process of changing color codes when it happened. It's just my truck test unit running 11.2 firmware. Going to 13.1.3 didn't fix, nor did going back to 10.5. Put in a real default plug and reset to defaults too. -Steve D
