I'm having exactly the same behavior from my plants... I guess my problem is really lack of light since they only get direct sunlight from 16 pm to 21 pm.
The funny thing is that I don't remember this from last year.
here's a couple of leaves on the Aji Amarillo plants I have going. They look like crap because they got shredded by hail a couple weeks ago. The ajis have huge leaves compared to all the other varieties in the pepper patch (12 I think??)-