Rings Unequipping

[MageBill]

Currently in my 2 ring slots I have an UC Steel Ring in the left one and a C Steel Ring in the middle one.

I drag'n'dropped the UC (the one on the left) into my inventory and found that, instead of the UC one unequipping, it unequipped the C.

Upon further investigation, it would appear that, to replace the ring in the left slot, you must unequip both rings, as by default the one on the right is unequipped first.

(Conversely, if it means anything, the Left slot is always filled first. The right ring slot cannot be filled unless you have 2 rings equipped.)