I live in a recently redone home and I'm having a very odd electrical issue. My microwave is intermittently tripping a combination arc fault breaker only when it is mostly empty, e.g. one slice of pizza. When the microwave is fuller, it works fine. The breaker does not seem to be the problem: I've moved the microwave to a different circuit and had the same results. I have a new Panasonic Inverter microwave; my old microwave exhibited this same problem. No other appliance in this home has caused any trips.
Breakers involved are Siemens QAF2 CAFCI.
Any ideas?