[renowner]

When Equipping a pocketed equipment, if you fill the extra item belt slot and then take the pocketed item off, you retain that item belt slot until you remove the item from that slot yourself.

Steps to replicate:
Equip a pocketed item.
Fill the new item belt slot with something.
Take off the pocketed item.
Notice how in battle and in the inventory screen, the item belt is still filled and completely functional.

[Neus]

This should be corrected in 2.77.