B1475 a/c Inverter intermittent failure?

Hi.
I had my a/c start blowing heat today while set at 65F all of a sudden (blower moving normal amount of air, just went from cold to hot in a matter of minutes during a drive). On inspection I discovered that my a/c compressor was not running with a/c in the on position and cooling fans were not running either. I held down steering wheel buttons for a/c auto and recirc. and power button to check codes and came up with 21 and 75 (B1475). I have no check engine light or “triangle of death”, but borrowed a obd2 scan tool from the local parts store anyway. It said there were no current or stored codes. Toyota diagnosis flow chart seems to indicate that I need to replace the entire inverter assy. However, after letting the car cool, I restarted and now have working cold a/c again. After that I immediately discovered that my inverter coolant pump is not running at all. Any thoughts? Why no code or warning for the inverter coolant pump? What are the odds that the inverter is OK, and maybe the only issue is that the inverter overheated enough to shut off the a/c compressor, but not damage the coolant temp sensor in the inverter or the inverter itself? It seems to be running and charging normally. This just happened today, but I have no idea how long the inverter coolant pump has not been running. Thanks for your time and any thoughts or info!