I have had them drown after pip simply because the air was too moist & they couldn't breathe. This was back when I 1st started & listened to everyone who said humidity needed to be like 80% for hatch. I lost a LOT of chicks who simply suffocated from all the moisture in the air. So whether you call that drowning or suffocating it's still high humidity during hatch that causes it.
that would be carbon dioxide poisoning
humid air holds less oxygen than dry air
so extremely high humidity will have less oxygen holding capacity than the same air if it were dry
so they don't drown.. they can't since the humidity won't drown them... they just die from lack of oxygen.. which I always make sure people know to leave all vents open at hatch
for goslings and muscovy I routinely have the humidity so high at hatch that there is condensation all over the window (and on occasion all over the walls) of the bator.. never have a problem with lack of oxygen because I do open the vents as far as they will go.. plus I open the bator on occasion to check their progress.. even when I open it I soak everything down with a few good spritzs of water so the humidity immediately climbs back up to 80% or better