By looking at your pics it has zipped all the way around but has not torn the membrane fully, not allowing it to pop the cap. The membrane should be fully torn all the way around just like the shell is. You may need to help it pop the cap by slowly pulling top section of egg until it breaks...
I use these attached to 4x4 fence post for pen, one on each side grit and OC. Been there for more than 7 years now, just drilled holes in bottom to not hold water.
All well here but just trying to avoid the mud this spring as it is one of the wettest springs in a long time. Hard for the nesting turkeys with all this mud.
Wettest spring I have had here in a very long time and I decided to not use my incubators. But did have my 1st batch set hatch 18 out of the first 24 eggs set. Wasn't expecting this hatch to be that great as it was the 3 to sometimes 4 hens in mass nest in shed. Should get better now starting...