Mitch did all I could expect to resolve an infrequent problem. Since the unit was working when he arrived it made things very challenging for him but he systematically worked through all possible causes and left with everything working fine. He assured me that a repeat of the problem would be addressed with a replacement thermostat without more expensive troubleshooting.
Response from Hendrix Heating & Air Conditioning, Ltd.:
Thank you for sending in your kind review-we really appreciate it!
Diagnostic - system wouldn’t turn off when thermostat was satisfied
Mitsubishi Ductless heat pump and ductless wall mount