Hardened Skin Ability (not working)

[SkriK]

I'm trying to use the "Hardened Skin" ability to temporarily block damage. I've set targets allowed to Ground and Air (which should work imo) but it doesn't. The standard Enemy and Allied didn't work either.

Hardened Skin is added using a trigger so the unit doesn't have it originally. So i'm wondering if it only work when researching it?

EDIT:
PROBLEM SOLVED!
The problem was due to me using "Channel" as the triggering ability which had the unit paused during the Hardened Skin duration.