Ahh the joys of hatching babies in captivity. It seems like you almost have to deal with wrapped up yolks yearly if you ask me. I would give it a day or so more and correct the issue if neccessary. There are a couple different ways to deal with it. First of you could pull the baby and the yolk out and untie them just like you would a knot being extremely careful not to rip the umbilicle off the baby or the yolk off the umbilicle. Put them in a tub with sopping wet paper towels in the incubator, kinda like a warm ICU for the lil guy. The second way would be to take some unscented/unflovered dental floss and tie the umbilicle off just down from the babies belly and cut the yolk away after the dental floss(kinda like a tourniquet). If at all possible you want the baby to absorb that yolk as it is the life system of the new baby. If you end up cutting the yolk away be prepared to force/assist feed that baby within a day or two of it emerging or it could pass, or worse off kink up due to lack of nourishment. Good luck and keep us posted.