When things act differently what is different.
You stated it worked fine at lower ambient temperature, so the issue may be related to ambient temperature.
The unit level of work is directly related to ambient temperature.
The higher the temp, the harder the compressor needs to work to get the condenser to do its job.
Measuring the voltage at the ped is no use.
You need to measure the voltage at the compressor, poor connections or too small a wire someplace will allow a drop in voltage.
And as the compressor works harder the voltage drop may be more.
IF when it is allowed to cool it will restart I suspect the thermal overload device is doing its job.
This is a disc located where the wires go into the compressor, when the compressor gets too hot it disconnects the power.
Considering it may be 108 outside the ambient heat alone is going to heat up the compressor some, if the voltage is lower the amperage is going to be higher to produce the same work.
And you are going to loose most of the effeciency of the unit, at 80 degrees it may be some percentage, it will drop 10 % at 95, who knows what it is at 108, maybe only 60%, the manufacturer can provide the exact detail there based on model number.
Higher amperage across the same resistance results in more heat.
Remove cover and clean out the condenser coils, dirt here makes for harder work.
Locate places to measure voltages, safely measure voltages both running and not running, compare to other unit.
Looking for difference, if front unit drops to 107 volts and the back unit drops to 110 there is a difference either in the wiring or the unit or the compressor is pulling more current.
You would need to be able to measure the actual current draw to know for sure, if both drawing similar current then the lower voltage indicates a bad connection.
Final note, ac compressors DO NOT like to operate on low voltage, this needs to be fixed soon as it can wipe out the compressor, the thermal shut off is doing what it is designed to do, you need to determine why.
Good luck and keep us posted!
Tony & Lori
1989 Country Coach Savannah SE