So this is my 3rd year growing serranos and I have not seen this before. The plants look healthy and green and are around 18in tall.
The leaves on some of the plants are folding upward like a taco shell. Some of the bottom leaves are leathery and brittle.
I am watering as it needs and giving it a 9-4-12 fertilizer every 7 days per the instructions. Checking for bugs everyday and have not found any.

Is this fine or is it an issue? Any help is much appreciated.

Is that fertilizer solid or liquid? Either way it seems to me you are giving far too much of it: even potted plants are generally fertilized every 2/3 weeks.

It is liquid. These plants are in the ground and the soil is fairly depleted of nutrients.

Here is the box. Not the same stuff I used as last year which was GH Flora Grow hydro nutrient set.

All clear now.
Folded leaves are a symptom of stress. In your plants' case I'd say this is a mixture of watering stress (to which some pepper and tomato cultivars are very prone) and and an excess of readily available nutrients in the ground. In short your plants are going nuts.

You should try reducing the frequency of fertilization (say once every 2/3 weeks) and set up a regular watering schedule (say once or twice a week according to the weather). You should also try to use that liquid fertilizer immediately after watering. The salts will distribute themselves more evenly in the moist ground and the roots won't have such a hard time extracting them.