The weird thing is I kept a much drier hatch than the two in the past and I didn't have these problems when I had excess humidity. I had a few chicks with mild navel issues in the past, just a bit swollen, but they healed fine. I also had eggs that didn't hatch so I pretty much knew the humidity was too high. I didn't have a single sticky chick when I had high humidity.
When we candled on day 18 the air cells looked pretty good I thought. I'll do my best to hold the humidity within normal range (65-70%) and think I will candle a couple right now just to check.
They aren't really late, day 21 is just barely starting (I set late at night, bad habit). But I haven't had this particular issue before. Thank you for the advice!