Rammus taunt reversed by dashes [Gameplay]

This bug has happened to me four times in the last week. The bug happened on the champions: Tristana, Lucien, Akali, and Riven. When the Lucien and Riven were taunted shortly after dashing, instead of being forces to attack/follow me during the taunt, they were slowed and walked in the opposite direction. The bug happened when I taunted during Tristana's rocket jump as well. I expected her to jump and turn for the duration of the taunt, but she instead continued walking away. The time with Akali was really strange though, she was level six attempting to ult at a low health teammate. She was out of range, so I taunted her before she could dash, but, once again, she was slowed and continued walking in the direction of my teammate (who was in the opposite direction of my character).

I'm sorry I can't provide step by step instructions, but I don't have recording software to save/analyze the games this happened in.

This all happened while I used the Guardian of the Sands Rammus.