Its happens when the humidity is way to low.
My humidity stays at 30-40% naturally with no water so for me normal hatching is dry until lockdown then water in the bator.
BUT with the wind and cold my bator had a little trouble keeping warm so lockdown was a bit longer then normal and I did not check the humidity till after it got really low.
I spent most of the day with a spray bottle of hot water... misting bator watching humidity meter.. spike then drop.. mist.. spike.. drop.. I finally got it leveled out at the 70%