Moisture control is designed to hold moisture so every few days could be overwatering. Also MG bagged soil usually only feeds the plants for 3 months and count it lucky if it actually does. I would start by fertilizing them.

Have you used any chemicals on them for pest control?

I sprayed them with some aphid control stuff a few months back but nothing since. Essentially all I do is shove the water meter in them, when they are showing close to "Dry" i'll water them..otherwise nothing..

Give them some balanced fertilizer and calcium. I've found that deformed leaves in otherwise non-diseased peppers are often due to nutrient deficiencies, especially calcium. It won't straighten out the deformed leaves, but new leaves will be healthy if that was the problem. And it's probably overdue for a fertilization regardless. They're "big eaters." Good luck!