I have had this problem as well a couple of times, but if I remember corectly only when using the UI buttons for abilities/potions etc. Sometimes you have to click 5-10 times to drink a potion for example. Everything works fine if you use keyboard shortcuts for sneak for example or rightclick on a potion and then "use" from inventory. Playing on steam.
Dude I have to click on at least my char to cast action surge. I clicked 30 times and it didn't work.
