Entities riding boats, minecarts or other entities are rendered too dark when their hitbox intersects solid blocks

The bug

Entities riding boats, minecarts or other entities are rendered too dark when their hitbox intersects solid blocks (i.e., the ground).

Known instances of this issue

• Riding a stranded boat
• Riding a minecart on a rail that is placed on solid blocks and is not a slope
• Spider jockeys

Video

Minecraft 19w45b 2019-11-10 16-36-40_Trim.mp4