Just got back from service where they replace my UMC. They looked at it right away and said it had to be replaced anyway because it was an early model and I heard something about a tech note on the 14-50 adapter. For those early sig owners out there, it might not be a bad thing to call your local service and ask them if you need to get yours replaced.
I dropped a note to my service center about this as well. I noted that my plug was getting very hot to the touch this weekend. I suspect I might be one of those "earlier" UMC holders.