you probably had full chi, the way it works is it adds a spark first, then consumes two. when you're with full chi, there is nothing to add so it will just consume 2 sparks. i see you also mentioned the skill taking 150 chi, it happens when you have 3.5 sparks, so the skill increases your chi to 399, then consumes 2 sparks which looks like 150 chi taken.
shh, it's just another skill I did hidden nerf to.
Agation pls nerf venomonster
No one gives a fk about sage wfs they're always full on chi anyway.