I hate when this happens...
So I have a cincinnata sprout who's primary leaves are still covered with that sack thingy... In my expierience if it's not removed the seedling is likely to die.
I've let it sit for 4 days to give it a chance to break the sack itself.. Decided today it needed some help.
It's delicate micro-surgery with a razor knife.. But I pulled it off without damaging anything.
While I have the camera out- Here's a few of my gracilis sprouts. They've been up for a week- ready to move into a bigger pot as the roots are growing out of the peat.