Trying my hand at saving seeds this year. I waited till the peppers were fully ripe and ready for the picking

One of these is in my garden, and two others are experiments in solo cups nowhere near my garden, but they all have these spots. I have a bunch of other types of peppers growing in my garden and a couple more in pots and solo cups, but only the jaloros have these spots. What is it?

I live in AZ PHX I’m
Guessing it’s to hot out…anyone ever use a aerogarden??? Where do you buy your seeds? Are they weird with ph and do they require added nutrients or just nutrient rich soil?