2112. big Rush fan???
The fridge can run off-level up to 3 degrees side to side (fridge's side not trailers) and 6 front to back.
I have never heard the 24 hour limit either.
The damage occurs as soon as the unit is off-level and the liquid chemicals no longer are able to flow down the coils. The boiler gets starved for liquid and the stuff in the boiler (anti-corrosion chemical I believe) literally starts to cook. You can cook some and the fridge will still work, but eventually enough cooked particles build up and cooling suffers. I have heard the cooking described as dried concrete on the sides of the boiler. The boiler being the part that the flame heats.
A series of 48 30 minute sessions would add up to 24 hours. assuming the 24 hour thing is a real number then those 48 times would ruin it.
Almost everyone has run the fridge off level and done some damage, it is hard to not. Turing it off when you park helps, but how much damage will be done in the time it takes the boiler to cool off to the point it will not cook? I do not know this.
For OP.
It sound like your fridge was always working.
If it worked again when temps cooled off then it always worked. Fridges are not finiky, they work then they dont work, there is no reverse unless it is an air-flow issue or other issues as mentioned. We need more details to help u.
The freezer works because that is where it is mostly cooled. The fridge portion will be much more affected by outside temps. The insulation is a part of this. The box simply cannot put enough cold into the fridge to counter the heat coming across your thin insulation. This is why it will not work above a certain temp.
Things that help:
*Keeping the fridge side of camper in the shade (north side away from sun) so the entire side of the camper is not so hot as to keep the fridge hot.
*Using a fan to move air across the fins behind the fridge.
*Use a baffle to direct the moving air across the fins and not letting air bypass the fins and go around.
*More insulation for the fridge sides, top, bottom and door if possible.
*Keep the fins inside the fridge free so air moves across them, even using a battery fan to help move air.
* Don't open door.
*Keep fridge full so there is more "mass" of cold things, and not just massless air so when you do open door no cold escapes.
* ^ don't let a full fridge block the interior fins.
*Remove the shaded side fridge compartment outer door.
*make sure there are no blockages in the fridge compartment flu that would block the moving air.
*Check that your propane flame is high when you have cooling on high. It should be a small flame when on low and a high flame when on high. This applies to some fridges, and others might have just one size flame that turns on and off when needed. Older styles had an adjustable flame and no way to control the fridge inside temp other than a manual set flame that does not know what is going on inside the fridge.
*set fridge temp as low as possible at night so it has farther to go to warm up during the day. Keep fruits and veggies on top so they do not freeze just in case...
Lots of threads about this very issue, you can find more tips by searching the 1,000s of post on same topic