Cannot Trigger Ultimate or Jack Abilities using KBM on Xbox One

So when using Keyboard and Mouse on xbox one, the game says Y to trigger ultimate abilities,and T to use Jack’s abilities, but when pressed nothing happens, I’ve even changed the key bindings to Mouse 4 and Mouse 5 and still the abilities wont trigger when said buttons are pressed. So I’m forced to quickly use the Xbox One controller to trigger ultimate or Jack then switch back to KBM. Not very convenient as you could imagine. Is there something I’m missing? Anybody else having this issue? Is there a fix, or at least one coming?

P.S. Sorry if there is already a thread about this, could not find it.