A few questions:
Was it hotter on the return trip?
Where is your genset located on your coach?
Were you in some traffic or not moving as fast creating airflow?
What time of the day?
We had a similar issue a few years ago and all of the above things came into play. It was hotter on the return trip, traffic had slowed thus limiting airflow, it was the middle of the day so the road temp was much higher, and the poorly insulated RV forced the AC to run non-stop.
And as you said it was running both AC's non stop. That's about 100% demand on an air cooled gen on a hot day stuck in an enclosed bin.
My guess is it reached the high temp shutdown. Especially if it started and ran after it cooled down. Happens a lot.
Like I said earlier, I installed a vented door for the genset bin and haven't had a problem since. Thor actually recognized their design flaw and paid for the vented bin door. It can simply come down to the model about where your genset is located. Near the engine, near the exhaust, in a bin with less air flow etc. A lot of manufacturers don't install them or vent them the way they need to be to get cooler airflow. They installed mine right behind the engine. How dumb is that? They have since modified the location.
But when it's all said and done you have an air cooled generator barely sized to run everything with a high temp limiter on a poorly insulated house stuck in an enclosed bin. Thank goodness it at least has the self protect shutdown.
