I keep mine running 24/7 year round and keep it set at 66 degrees and my hygro's usually read within 1 or 2 degrees of the setting and I have them in the front of the unit. I would trust your hygros before the coolers temp gauge. But keep in mind even a good hygro cannot be considered 100% reliable. I have learned to not freak out every time I see a few degrees or percent swing. When you get sudden spikes of 5+ then I tend to get a little paranoid

I would give it a full 24 hours and let everything stabilize.