To follow up on this one, i suspect this sensor is faulty and likely has been for a while. Put in even more backup checks of humidity and temp and this sensor is up to 3 degrees higher or lower with...

I'm incubating chickens and I have the sensor hanging from the roof of the incubator. It was accurate untill day 14 when the temp on the sensor suddenly sharply spiked to a lethal temp for chicken...