Triggers are pretty common on modern game pads, and I heard the OOO staff are pretty fond of using game pads themselves so I find it kind of odd that this bug has never been addressed.

On my pad, holding the right trigger disables all functionality of the left one. This is due to both triggers acting as if they're opposite sides of the same axis. I believe this is something you're able to fix on your end, because I can play lots of other games using both triggers simultaneously. As an example, many modern shooters lets you aim precisely by holding the left trigger while firing using the right one, and on those games the triggers behave as separate buttons just like they're supposed to.

In Spiral Knights, this lack of separation can cause many issues:
-If the left trigger is used for blocking and the right one for attacking, the player will not be able to shield-charge.
-If the left trigger is used for auto-target and the right one for attacking, the player will lose their target when attacking, which kind of negates the auto-target's entire purpose.
-If the left trigger is used for blocking and the right one for strafing, the player will not be able to shield while strafing.

There's all kinds of other issues that could potentially crop up, like players lowering their shields to swap weapons, but the three cases above are issues I've personally run into and represent how this issue affects me.