plants look great, sometimes they just do that. We are growing sandias and some are perfect and straight and some are curled.
I don't know what causes it, but there isnothing wrong with the fruit normally and it just looks a little weird. I have also seen this on thai, cayenne, etc anything that grows long and skinny, even the occasional jalepeno.

kendra

I think is caused by poor or incomplete pollination. Trying to think where I read that. Give me some time and will reply again. I remember the website owner name was Dave Green. (I think)

This is the website. I can't seem to find the pictures that I want though. :( Past my bedtime & maybe tomorrow will have better luck.

Reasonably sure about my original answer.

jt

Here is a link that might be useful: http://www.pollinator.com/

i agree kendra get it all the time on long chillis and also agree with jt bad pollination only way to stop is to pollinate with a small paint brush or buy bees

dan

LET IT BURN

Thanks for everyone's input. It's been puzzling. I haven't noticed any other deformities and I'm growing about 12-14 varieties of peppers currently.