Just to close this out, it was a lack of power.
I removed the display panel above the freezer and this gives access to the main fuse and critical wiring. It was immediately clear that the
12V wire from the converter was dangling free. Airstream uses those Wago lever nuts to electrically connect wires throughout the trailer but it's a bad choice in this case. Stranded 12 gauge wire barely fits into these lever nuts and it's clear that they just jammed the wire in without ensuing a firm connection. No surprise that it came loose.
Thankfully this was an easy fix.