Higher humidity = lower temp readings?

For the longest time I had been relying on the water bowl and very occasional misting to keep the humidity around 50%, but I bumped it up to 65-70% for a shed cycle. The problem is my digital thermometer broke so I've been relying on the old dial thm that I never took off. It's always read 85 degrees when the warm/cool sides were right where they needed to be. Since I bumped up the humidity (and its been no colder in the room than usual) to the 65%, its been about 5 degrees cooler on the thm. Nothing else has changed (covering, heat lamp position/strength, etc).

I mean I guess it makes sense that the humidity would wick away heat a little bit.. but still... anyone else experienced this?

Actually humid air holds heat better so I don't think thats the problem.

But, you have a thermostat controlling the heat source; is this right?

A lot of evaporation could cause a drop in temps. Thats basically the way AC works. Maybe less ventilation is in order?