Mine had that too, did you harden them off? It could be sun damage.

It's mildew so far as I can tell from this pic. There are mild soaps that can be diluted and sprayed onto plants in order to eliminate it and save the leaves. Otherwise, if this is mildew, your plant will eventually (likely anyway) drop its leaves and then try to re-grow them and start over. I experience this with my indoor started tomato plants just about every year.

thanks, it was actually easy to wipe off, basically few drops of water got rid of spots or coating, or whatever midlew it is, been using now neem oil mix with little soap in water on leaves as well.

Excellent!

Looks like MILDEW to me too. But I have never seen mildew on peppers. It mostly affects cucurbita family of plants.
It is possible that what you have is some kind of other mold.
I would spray with Neem Oil spray.. Milk and water ( 20/80 ?) is also a home brew for mildew.

Sey