I’ve seen a lot of thermostat pistons that set heating and cooling points sequentially (see screenshot) in a piston and I’ve read that people have issues with thermostats issuing both of the commands. My thermostat was only setting the heating point and ignoring the command to set cooling point. For once found a solution myself (not to say someone else hasn’t done this) so I’m sharing my solution - a restriction to current thermostat mode.
What brand of Thermostat? I know with the Ecobee I had an issue as well. Turns out that while I was able to adjust the buffer gap between cold and heat points in Ecobee , SmartThings hard coded a 5 degree separation between Heat and Cold points. So one would never set. Many thing about ST implementation of thermostats I just dont like. Ive had to go and reinvent the wheel by using Webcore.
I have Honeywell thermostats