Vi ult got canceled

Does anyone know what cancels Vi ult or if it has a max range?

Enemy was doing drag and we went to contest it. When Lucian ulted I ulted Lucian. I could clearly see the line and the animation... Lucian kept moving away as my ult was bringing me to him and then he dashed... and some how my ult just stopped. Never seen that before. I've seen Vi ult survive crazy stuff even to the point they move/flash under their tower making me severely displaced.

Anyone know?