My stepmom has a few garden boxes in the back yard, in one of which she is growing "Cute Stuff" red, yellow, and green peppers. The green peppers don't really have any peppers on them yet, but seem to be starting to grow some.

The red and yellow peppers, on the other hand, have a few small (about an inch long), green fruits beginning to grow. They are firm and shiny, not rotten or soft and seem to be very healthy. Yet, for some reason, they are turning black on the bottoms, and the joints on the plants where the stems meet the stalk are blackish in color. I've attached a photograph of one of the red peppers with the strange coloration.

Is this normal? It's hard to research, since "black peppers" are another kind of pepper. Some sites I've read seem to think this is just part of their color transition. Others say it's a disease or lack of calcium. Most photos I find have rotten peppers, but other than the odd pigmentation, these peppers seem to be fine.

Any help would be greatly appreciated! I know nothing about growing peppers so I'm hoping this lovely community could help us out :)

PS: The yellow pepper has small, almost pinhead sized brownish-tan spots on a couple of the leaves. Other leaves are fine. Is that normal?