I spec into Bladed Focus for my Sentinel Multistrike ability to consume all stacks of Armament to restore mana per stack. This is rarely working and there is no clear indication on what/when exactly trigger it. I tested out by having stacks of armament and then just keep using Javalin to reduce my mana below 0 but it is not consuming the stacks to restore mana. The only time I see it work sometimes is when I have stacks and then use Lunge but it is not guaranteed.