When I first posted this question I hadn't paid close enough attention to the duration between short cycles. It seemed like it was 5+ mins maybe. But the next time it started doing it my wife used her phone to time it. The time between short cycles was between 1 min 07 seconds and 1 min 40 seconds.
That's the air conditioner stopping to a full-stop every min and restarting and doing it over and over and over again. And, while the fan is most noticeable when it stops it's also true that the compressor is kicking in on the restart 1 second later.
I can understand that the unit could freeze up - and shut down to thaw the coils. But why would it only stay stopped for a second or two before restarting. So, I don't see how it could be that.
I can also understand that if a vent is blowing on the thermostat that it could prematurely tell the A/C to stop. But, I don't see how it could do this once per minute for 90 mins.
Plus, neither the freezing nor the vent blowing on the thermostat would explain why the problem goes away when the unit is set to LO or HI.
It must be that either the thermostat on the wall has a problem or the control unit in the A/C has a problem.
2015 Forester 3051S
TOAD: 2016 Lincoln MKX