When I was using my MCO underfloor heating thermostats with my Fibaro HomeCenter 2 Gateway, I also had short temperature peaks from time to time.
Since I connected them to Homey (about 1 year), the problem has never occurred again.
Therefore I guess that it could have something to do with handling of the Z-Wave data in HC2 or in Homey.
But as I said, it is only a guess.
