Elise Mains owner here, its the Self cast rappel bug.
If you Alt-E (self casting even with your cursor on the map and nothing else), while standing too close inside a target model, you will drop back down and it will be treated like a targetted rappel. This applies to all units, not just champions.
Here's a demonstration;
https://www.youtube.com/watch?v=t78PhtVyaYA, note my cursor's location, literally no where near the target, and I get the targetted rappel buff (spider queen amp) when that's exclusive to E1 targetted rappel.
and when I said all units, I meant literally all of them, we even started practicing this new mechanic with plants to escape over the walls and the bug as been ignored for so long some of us have gotten good at it: https://streamable.com/raq4eo
This bug has been in the game for years actually. Its extremely frustrating and game losing even, since self casting rappel is the only way she can go up reliably without clicking on the champion she's fighting for ground casting.
The bugs that were introduced with the VFX update were hotfixed, this is the one that elise players have been trying to get fixed for pretty much a year now (only because we discovered how to replicate it, before we just assumed it was in our heads but once we learned how to replicate it, its all out in the open now.).
Its potentially winrate influencing, so many of us lose games dropping when we didn't mean to (on a champion that can't be set behind no less..). We hate the state the champion is in rn and the bug just sucks so much. (for the love of god can we buff her clear even a tiny bit? Its actually painful to do camps post level 3 she cannot keep up with any junglers and has to coinflip dives to stay relevant... buff W attack speed, monster caps, neurotoxin amped damage to camps, something...)