Rammus taunt acting strange on Fiora in 3v3

Just played a normal 3v3 with some friends as Rammus. Fiora reacted three different ways to my taunt. The first way, as normal. The second way, she would get taunted but it would last as long as the animation (she did not have any built tenacity). The third way, she would run away. This occurred once with no minions around for it to be caused by some sort of pathing error. I'm sorry that I don't have a video or screenshots. None of the three ways seemed to happen more than the others or in any sort of pattern. We theorize that it may have something to do with her riposte, but not sure. Thank you, Kuita