Im with Dean. The misting may have triggered something and SYR has some good points too.
The first clutch of Kinyongia tavetana eggs I hatched out did the same after I added more moisture. Luckily only half of them hatched or popped too early and the rest were alright.
I used a smaller container which held less vermiculite because they have smaller clutches than what I was use to dealing with (panthers). It caused the medium to dry out quicker and I had to keep adding water to keep it moist. Now I use large containers no matter how many eggs are in there. This way I can put lots of vermiculite to hold more moisture. I also started not poking any holes in the containers and just putting the lids on opening them once a month or so to look and get fresh air in there.
Hope the rest hatch out properly for you.