rumble ult when cced

1. Play rumble vs a champion with a cc (might be only knockups im not sure).
2. Aim equaliser while cced and finish using it before the cc is over.
3. When the cc effect is over the equaliser will be shot but at a different position usually just out of your screen view.

Note: it seems to land at the same angle and at the same line as where originaly aimed, but further up the line.

This is pretty close to 100% chance of working it happens in about 50% of my rumble games and had been happening since I can remember in season 3.

update: just found out that the same thing happens if the same thing is done but while channelling teleport, here is a link: https://www.youtube.com/watch?v=CsGSfcdEq58