m0useanswered grow question 3 years ago This happens sometimes, I germinate my seeds a bit different to prevent this from happening.
I scarify the seeds using a emery board in my palm just rubbing it around lightly in circles. I give the flat end of the seed a little nick with the same emery board and soak it in water for 12 hr's, after all that I plant it in the hole directly in the medium with a mycorrhizae inoculant to helps the root get a good foot hold.
This should help prevent that from happening. Older seeds will take longer to pop as well.
The other recommendation is great as well. spray it a lot and use tweezers to try and help it break free of the shell. Don't force it though, if its cotyledon "first leaves" are damaged your seed is over.
Good Luck!