Pioneer floor mount does act similar to what is described for the Senville floor mount.
It is a strange thing, my thoughts are it is the outside condensing unit core temp sensor is defective only at certain temps. I was going to pull it out someday and graph it on my graphing multimeter as I run it thru the temp range. But then it started working perfectly fine so it might be just a bad connection, until last night I decided to turn it on for a little heat after it had been used for air conditioning for quite a number of days. It went into the defrost cycle right away. I have enough to do now so will probably not look at it until fall.
The Pioneer works very well otherwise. My Senville wall mount can get a little cantankerous too. I prefer the Senville except for the wi fi app that uses Alexa app, what a joke.