I have two thermometer/hygrometers that I have used for 4 years now the same ones. I have never had a problem with them being right on the money. Walmart specials.
So I agree to disagree.
I'm not up on air vents in LG but maybe Insufficient Oxygen if the vent plugs need to be pulled? I would also get new thermometer/hygrometers incase yours are off, two different ones set in the bator. Check your batteries also, I dry my thermometer/hygrometers out after each hatch and add new...