Well, this was an early pepper, the first off this plant, so maybe it's a seasonal thing.
Hm, I wonder...remember how we talked about pinching off those first few buds? I wonder if the lack of seeds is related to the immaturity of the plant. Like Pepp3rFreak said, it's shooting blanks because it's producing peppers so quickly. This was one of the last peppers I put in the garden, and I didn't pinch it back.
Or, I wonder if it might be environmental. I put a lot of mushroom compost in that part of the garden. It's new this year, I just got several small stumps dug up this spring, and I thought the mushroom compost might jump start things a bit since I didn't have time to amend the soil properly.