I had a Mitsubishi M-series H2I single zone mini-split installed in the bedroom this past summer and I am using it for the first time this winter season. I live in the SF Bay area where generally the overnight temp is in the 40's. On a couple of occasions when the temperature has been in the mid 30's and the unit has run a defrost cycle during the night I've found that after the defrost cycle completes the unit will return to on but produce no heat. I leave the unit completely off during the day and it has always worked fine the next night. Any ideas on why my system is operating this way?