Sometimes the menu that comes up when I hold the left-shift key is completely non-functional. My abilities are off cooldown, and indeed work just fine if I trigger them using hotkeys. But I can't trigger them off the shift menu, nor can I tell me allies to use abilities or even get the weapon selection UI to come up. One I reach this state, I seem to stay in it permanently. I usually end up reloading a saved game and then it works again.
Is this an in-game effect, or a bug? In either case, what triggers it and is there any way out of it short of a reload?