Or it could be lack of calcium, like blossom end rot on tomatoes. I get that on peppers and tomatoes especially after a lot of rain so now when I spray my tomatoes with blossom end rot spray, I spray the peppers too. So far no yuck spots on either this year.
Concur with rtl850nomore, that is sunscald. Blossom end rot (BER) does occur on peppers, but it appears on the blossom end not the shoulders. Both peppers and tomatoes tend to outgrow it as the plant catches up with demand. It is stress related. Sunscald is prevented by adequate leaf cover. Wet fruits in the sunshine are especially susceptible as the water droplets on the fruit tend to act as magnifying glasses. Bottom line , don't overhead water peppers in the daytime.
My peppers are unruly and keep peaking out of the leaf cover. I have shade cloth for the afternoon sun but in this hostile desert sunburn is expected. I just cut out the bad spot and use the rest of the pepper. My fall flush is less likely to experience sunburn.
Well, they were growing under the cover of the upper leaves until the blasted hornworms showed up. Grrr!! Maybe I can get my DH to devise some kind of shade tent for them during the heat of the afternoon out of some solar screen or something like that.
This could have started as sun scald and moved on to something bacterial. If you see spots on your peppers you should remove them immediately. You can cut away the affected area and use the pepper or chop it and store as is. Peppers don't need to be blanched to be used for later cooked. Sweet pepper varieties are predisposed to sunscald more than hotter ones. I have to pick a fair percentage of mine early because of spots. They come off the plant the minute there are any symptoms. No use in wasting the plant's energy growing damaged fruit.
This July had an unusually hot period. During this time the peppers did not bloom. They are in very rich soil and when it cooled some, they went into blooming overtime and have such a heavy load of peppers that branches are collapsing from the weight.