So through the membrane I can see what appears to be a small amount of yellow it doesn't look like yolk, it looks like pale yellow scrambled egg. The blood vessels are 99 percent gone. Just waiting a little longer but the yellow stuff is concerning. Any thoughts?
Probably just excrement.
I usually see a little gunk in the bottom of the egg after hatch, but can't normally see it on an assist, so its hard to guess.