Has the gen been run since the earlier power surge? Did things work ok? Or is this the first time since then? Anything else get fried in that power surge? (would a transfer switch fry from that?)
Must have been batteries besides the fridge as part of the converter's load--any changes to batteries or wiring from them?
Maybe not turn on any 120v items in the rig when on gen just yet, but with the gen running check the 120v with a three-light tester and a voltmeter before turning anything on that might get fried too.
What is the model of the new converter? Warranty? Can you return to the workshop that installed it?
BTW you can charge your batteries with an ordinary battery charger until you get a converter, and run the rig's 12v from battery, while still being able to run the 120v stuff from inverter, shore power, or generator (if the gen runs them ok)