Questing with my friend Warden <-- me and Shadowknight --> Him // Sure enough Roots were happening. Not Stifles, not stuns, full on root w/ chains and all. We were basically hugging so it wasn't an issue of range. Just thought I would share.
I honestly haven't noticed that problem yet. So far, the only times I've been stopped in my tracks with this buff up is on stun or knockdown type debuffs. Where and on what mobs were you seeing this not work? I'd like to test it out and confirm, if possible.