With Amarasta’s Blade Burst bound to an ABXY button, pressing and holding the button activates ABB and continues to use normal attacks while ABB is on cooldown. Pressing the button ABB is bound to while ABB is on cooldown will result in a normal attack. This is expected behavior.
With ABB bound to L/R trigger, pressing and holding the trigger results in a single ABB activation. Generally ABB will continue to activate again after cooldown, but no normal attacks happen in between. Pressing the trigger ABB is bound to while ABB is on cooldown results in a “This skill is not ready” message and no other action.
If ABB is bound to trigger, activated, and held down, ABB will activate again after cooldown. If instead ABB is activated, then the trigger is released, then pressed and held again while ABB is on cooldown, ABB will not activate once cooldown is finished.
Tested on 1.3.0.8 on GOG and 1.3.1.1 on Steam, using 8Bitdo Pro 2 and XBox wireless controllers.