There seems to be a bug when using the 3BAv2 version.
The calves visually disappear when loading a game with the elven top and calves equipped. However, if you unequip the top, the calves appear on the body again. If you equip the top, the calves once again disappear. Inventory shows calves are still equipped, but it's not shown visually on the body.
Oddly enough, if you quicksave with both the calves and top equipped, and then quickload, they both appear together on the body again. However, normal saving/loading will reproduce the visual glitch of the calves disappearing...