You mentioned you were using the microwave when the power went out.
1. What amperage is your FR3?
2. If it’s 30 amp, I suspect somebody somewhere in your rig turned something else on at the same time, and you tripped the breaker.
3. At 30 amp, DO NOT turn on air conditioners at the same time, or hair dryers, or toaster, or electric water heater, or electric fry pans etc etc etc. Any appliance which is basically a controlled “short circuit” is too much at the same time on 30 amp.
Ken and Terry
2018 Sunseeker 2430S with Trekker cap
and only rarely pushed by our 2017 GMC Terrain toad (4 wheels down)
Former Georgetown 330TS owner for 10 years with more mods than I can count.