Seeds of several varieties of peppers of mine have that shape. It's nothing to worry about.

Tom

What kentishman said.

Sounds good, thanks...

It might be a sign of uneven drying - dry on the up side and still moist on the down side. I make a point to stir my seeds as they dry. (Actually flipping them over would require tweezers, a microscope, and way too much time.)

I should have put them on top of a paper towel.....