Past ripe. As the peppers cross over from ideal into the over-ripe stage the moisture in the walls of the pepper is drawn into the seed cavity. Heat and humidity combine to cause molding.

Red Beauty, like most bell peppers, are actually ripe when still green and just beginning to blush with color. Picked at that point and placed into a protected environment indoors they will continue to develop the color. When left on the vine to develop full color it is easy to let them go too long.

Commercial peppers are ripened off-the vine to full color using ethylene gas. Home gardeners can't and wouldn't want to do that. That, plus the reduced crop leaving them on the vine causes are just a couple of the reasons why growing any of the colored peppers is more difficult for home gardeners.

They are still fine to eat as long as the mold has not invated the tissue itself.

The non-mouldy seeds can be saved and will germinate but since it is a hybrid variety it won't breed true. If you want to save seeds then pick some peppers much earlier than full red and save those seeds.

Dave