I've been having problems with the bottom leaves falling off. At first thought was a rabbit but all the leaves are laying on the dirt, so l don't think it's that.
Certified GKH Gardening Expert
If the peppers look ok otherwise, it's likely the hot temps many of us have been experiencing this year, which can quickly stress out plants. Have they gotten sufficient water during this time? You can try giving the plants a good soaking. Also, mulch around the plants to help retain moisture. This is especially helpful when it gets hot and dry.