I just went direct XLR - to - PA, plus a 1/4" out to a Carvin AG100D as a monitor.
This has happened at home too, where I just go into the same Carvin amp.
I always use the same guitar and (almost always) the same cable. As I said, I have never had this happen with my Boss GT-10 unit (which I set up exactly the same), but it's happened a few times with the POD - mostly at home (this was the 1st time I've played out with the POD). There were no hints of trouble during any of the practices or the sound check, or even through the first half of the set. It was sudden, lasted about 30 seconds, and then everything worked fine after that.
I might have to send it in for service. My fear is that since it happens so infrequently, it won't happen when they test it ;)
But it makes me very hesitant to play out with it again.