I have a Vitrifrigio BD 35 with keel cooler.
It will occasionally do the same thing when loaded with warm stuff, and outside temps are hot.
I have a ducted fan in the box running whenever the box is being used (not just when the compressor is running).
I also have a good sized fan with a 140 f. snap disc switch mounted on top of the compressor to exhaust
air when it gets hot.
That fan is supplied with A12 volts so it runs whenever needed.
I suspect the refrigerant charge might not be quite enough for those conditions.
With all the "energy saving" numbers manufacturers want to meet, I suspect they are missing the boat with actual real conditions "horsepower" needed to do the job.
In our case, shutting it off for an hour or two does the trick.
We have learned it's important when running a small compressor not to expect it to move mountains, but we CAN keep ice cream hard as a rock and have full batteries as well.