Quick stock does not have error catching. When I attempted to put a potion in my armory, mistakenly thinking that would equip it to my primary pet, it instead put this tier 0 useless weapon in my armory, allowing me to use it as an unbreakable, useless item.

This is a known issue with the quickstock. The potion was likely deweaponized at some point but can still be added via the quickstock. Are you certain it is useless (as in it cannot be used at all)?

I tried using it as a weapon. It let me select it, but didn't even display a blurb on the center. It claims to be a Tier 0 One Use Dark Light potion when I hover over it in the Armory, but for some reason has 1 modification space, and even when selected in battle, does nothing. I tried using it again, to no avail. Sorry about posting on a known issue.

Which potion is it?

It is actually a Dark Light pot.

Hmh, so it looks like it can still be equipped to your pet as a potion but not used as a weapon even though it can be added to the armory via quickstock.

As I previously mentioned though, this issue with the quickstock is pretty well known. I'm not certain if it is being kept this way on purpose or not. In any case, you are able to remove the potion from the armory page in the Battle Colosseum. :)

Thanks !