m0useanswered grow question a month ago Could try different germination method with them seeds. Seems more like a seed issue and maybe its sensitive to the medium?
If the medium has a bunch of stuff in it I would use something simpler to eliminate that possibility of to munch at once.
Real simple mix. perlite, coir/peat and some compost. stupid simple. 30% perlite, 20-30% compost, 40-50% coir/peat
Some seeds are just bad at being plants. Giving the other plants where fine it looks more like its a strain specific thing or a bad batch of seeds.
I had something like this reticently with CBG seeds, from my experience with it all they are "special needs" and need a bit more love to get going vs other seeds. Maybe this is from how they bread them to be CBG dominate or something else. No idea, but I switched my medium and germination method and it helped with the ones I had extra seeds of. I also soaked them for 12 hrs to help that outer shell loosen up a bit. some soak for 24-48hrs. I find its to long but to each their own. If u suspect some other things like bacteria/fungal issues you can soak the seeds in 3% peroxide for 5-15 min then regular water, will help kill off any of the spores/bacteria on the shell that maybe pathogenic.
When things die at the base of the plant chances are its from "dampening off" a type of fungus, but I normally see this at the soil level not the growth tip of the seeding, it can be avoided by using new seed starting mix that is pasteurized.