After returning from a lovely visit to my family in Chicago I came back to this. Sweet peppers rotting from the outside, but only 2 or 3 and only on one plant. I thought it was some bug or something slowly eating away at the skin, but after some research I discovered it was sunscald. Yes, vegetables can get sunburn. These peppers were the only ones affected because they were the only ones not shaded by leaves. The affected areas had a dry, papery texture and the fruit as a whole felt soft/borderline mushy. I just snipped them off.