Siphoning Strike cannot build Combo

I have my Flicker Strike supported by Combo Finisher II. Even though I'm using Same weapon and the strike is successfully hit, Siphoning Strike cannot correctly build up Combo for Flicker Strike, while other skills can do. On the other side, I've checked the tags of Siphoning Strike, it counts as Strike.

Bump. Siphoning strike should build combo; it has the 'strike' tag; but it doesn't.