I think, though I could be wrong, but I took it as someone told her that it probably hadn't (would not have had) asborbed the yolk at the time it pipped. I hear a lot of people saying that chicks don't absorb yolk until after they pip and that's what takes so long. While there are times that the yolk isn't absorbed before the external pip or even hatch, in general, on the incubation/chick development timeline, that generally takes place day 19/20, so unless you have early pippers, the occasion that at day 21 there is still unabsorbed yolk, should be few and not the norm.
I run 75% at hatch and often it shoots to 85-90% I don't worry about high unless I see condensation.
It seems like the humidity gets higher as they hatch,or am I imagining that?
Always wonder about that.(a good point for me to store in my chicken vault)!
Sorry to hear that.