Did you move them outside into direct sunlight and then get spots? I'm almost positive those spots are sunburn. Why spots? Moisture droplets. They work like little magnifying glasses. It's one of the most common results from not hardening plants off prior to transplant outdoors. It's also why it is highly recommended you do not water plants during sunny days in a soil garden. The drops will cause the plants to burn, especially if they have yet to form a good cuticle (tough, waxy, protective layer). Of course, that is always the case in young pepper plants. You may not have watered the leaves or gotten them wet. It could have easily been due to moisture from transpiration.
So, don't worry. Not a deficiency or a disease. It also won't go away. As soon as you have a few leaves without the spots to compensate, clip those damaged ones off.
I also practice intensive gardening in soil. Be aware that hydro plants will require twice as much room in half the time under good conditions. I made the mistake of thinking my hydro peppers would be the same size as my soil peppers. . . .once. I also gave them way too much nitrogen, though. I made the mistake of following the instructions on the bottle. Peppers don't need a high
nutrient content.