About 1/3 of my bell peppers develop light tan spots ranging in size from Lincoln's head on a penny to 1" wide and longer. The spot is soft to the touch, yielding. They are in full sun exposure and shaded makes no difference to development of the spot. Irrigation is consistently once per day.
The container they are growing in has composted organic medium 50/50 with native soils. It is well drained. I fertilized every two weeks with Miracle Grow general fertilizer via garden hose metering applicator by Miracle Grow. What is this thing? Thanks.
Ask your county's volunteer master gardeners. They would be accessible through the cooperative extension office in your state. Just google cooperative extension, and you're there. They love to come check out what you have.
My peppers have done the SAME THING for YEARS! I have never learned how to stop it. I pull the pepper and cut out the spot and either cook it or FREEZE the pepper for use come winter! I have tried Adding calcium and using Epsom salts spray but NOTHING I've done seems to work. GOOD LUCK!