[Nexus Blitz] Ahri's charm doesn't CC scuttle in Scuttle racing at all

At first I thought it was reasonable as charm would make it go backwards.

Then I saw that Vayne can condemn the crab backwards. Anivia can block the crab with a wall. Alistar can headbutt it backwards. Etc...

Why doesn't ahri's charm make the crab walk towards her slowly? If I charm it from behind, it should walk back up the track. The way it is, I don't think charm even applies the slow.