Yep, two of us are going to say that when a seed sprout shows its roots, it somehow worked its way too close to the surface. It's not unusual to see one or two do that every now and then. If I get two or three in a pot, then I figure I sowed the whole pot too shallow and I just hand sift a little of mix over all of them. I think (I suspect) some seeds like to be sowed a little deeper than others and that's why you might experience it with a single pot more, while all the other seed lots are just fine.
It's interesting to note Rick's comment that little baby bulbs don't pull themselves down until the anchor roots contact over Fall and Winter seasons. Very True. Here's an example: Earlier this Spring I transplanted one of my best liked seedling lots into larger pots (my pets). An exploratory last Fall showed the bulbs to be just a little ever 5/8 inches below the sufface. This Spring they were about 1 and 1/2" to 1 and 3/4" inches deep! A very dramatic pull down.
Not sure if you're refering to about seed cases? Are you refering the seed hull being trapped in the soil causing the tip of cotyledon to be held down? Usually that can be freed up with a tooth pick. But if not don't worry, they'll shoot up a true leaf anyway. But send pictures--a picture is worth a thousand words.
