Hmm. The paragraph where this happened is this:

"Fangir might have a chance to recognize what was really going on now, as the real Champion materialized out of the mist behind him and slammed a gauntlet into his now slowed flesh from behind, while the illusion veiled ice sculpture in front of him, designed to guide Fangir's attacks towards Soran, melted instantly away. The gauntlet, though unable to penetrate the oaken flesh, sent mystic ice flooding over his limbs to restrict Fangir's form and magic. The Champions form also began armoring itself in ice, as though he expected to whether an attack."

The phrasing 'slammed his gauntlet into his now slowed flesh from behind' made me think of it as a punch. The thing about punches is that it would be hard to keep your fist in contact with what it hit even if you were to try, because the force almost always propels the person backwards to an extent while Newton's Third Law of Motion would mean that the blow itself would push your fist back towards you.

That was just the reasoning behind my interpretation, anyway. It makes sense that if ice appeared upon contact, the gauntlet could stick and contact could be maintained. The issue then is that if it's stuck really good the champion will have a hard time getting his hand free, whereas if it isn't then Fangir could probably break loose with ease.