The m248 does this as well.
Damn right it does...mine did it last night at the Truckers. I raised the gain and was able to get through the end of the show. Haven't listened to it yet to see how bad it sounds...I'm guessing bad.
FWIW, I've had my 148 do it as well although for whatever reason w/ the 148 it seems to be more sudden. It was definitely the batteries in my case though...your issue is obviously different.
Mitch