If I have 2 (or more) of the same weapon in the armory, and have different weapons mods equipped to them, the system always wants to use the first weapon I added to the armory even when I pick a different one. This feels very similar to the inventory lock bug where when you have an item locked and click the one that's NOT locked, it will often still choose the locked one.

Example: I have 2 weapons that are the same, but have different mod crystals. I set weapon 2 as the weapon I want to use, but when I go into battle it uses weapon 1, with the other set of crystals.

If I put both weapons in the battle set, AND use them on the same round, it does use both with different results based on the crystals. However, even if I put two in the battle set and only choose one to battle with, it will battle with the first one, no matter which I actually choose.