^^^
There is a good chance that they either did not get all of the air and moisture out of the system after all (possibly due to an unfound leak, as indicated by one of your vacuum charts), or did not add the proper amount of refrigerant (too much or too little), given the strange rise in evaporator temps even when the compressor is running.
Mini-splits come with the compressor pre-loaded with refrigerant that is sufficient for whatever length of piping the install manual specifies (more must be added if that length is exceeded); with your complex system (multiple evaporators/head units), I'm betting the installers did not correctly calculate how much additional refrigerant to add.
When set up correctly, those Mitsubishi's are capable of bone chilling cooling, way beyond what a normal person (me being abnormal!
) would ever want.