ARB states in the manual that their fridges will go 122*f below the ambient temperature, You are lucky to be alive, because running a fridge in those temps is a crazy thing to do, the standard pressure for that type of fridge gas would be multiplied by at leased 12 times and not only that it would cause your fridge to leak meaning that if it was better when it was new then the damage has already been done,When my Indel B 50 was new and when my house batteries were new, that fridge would hold -22C when outside ambient touched 128F in mid-afternoon. Fridge had been pre-chilled, some of the stuff went in frozen, fridge was near full, had a pile of clothing (insulation) on top of the fridge, factory window tint, white truck, etc. That was a huge drain on the batteries, but it worked as long as we moved around a couple times per day, usually 70-100 miles per day on a 270amp alternator. Stay parked and the batteries were done in maybe 18 hours. Interior cabin temps would go north of 185F, so delta was about 193F. My ARB 50 can't do that, even though it's new.
If a fridge is going to be run in those type of temperatures then it needs another type of Gas inside it, because the fridge gas r134a is not meant to be used in such high temperatures.