There is a bug in the spider form of Elise that if u E to dodge an ability or trying to get out of a situation, it automatically jumps on an enemy champion without even clicking on the enemy champion or press E. So when the mouse is on the enemy champion, it activates the E without pressing any keys to jump back.
I don't think this is considered a bug, if I understand right. I'm guessing you're talking about smart-casting with the cursor over the enemy champion. Thing is, Rappel always has to have a target. So, if your cursor is over an enemy, that means you have selected that enemy to Rappel to. If, instead, you want to Rappel straight up, the target absolutely must be the ground. The cursor is a slight annoyance to deal with on her, but in mechanics, the ability reacts slightly differently when cast upon an enemy instead of the ground, so the distinction must be made on which you are targeting.
If it's something else, I'd imagine something needs clarified on the situation. Her Rappel acts wonky sometimes, but it's about a 1 in 200 thing for me, if that, and this makes it sound like an every instance occurrence. It'd also need clarified what causes it, as I can't really say what causes the issue, so reproducing it would be somewhat difficult to accomplish. Most instances of issues, for me, happen in congested fights of some sort, usually, and generally deal with some sort of CC preventing Rappel from going off earlier, I'd say. But I have no guarantees on that, and can't reproduce because I can't find anything slightly solid for why the issue happened.
