GAMEPLAY, Vi Ulti Ability Bug

Hello! Yesterday, I have played Vi and noticed a strange feature. When enemy champion (Ezreal) was recalling, i have pressed "R" Ulty with Vi on him the last second of his recall i assume. Than he sucessfuly recalled but my ulty went on cooldown. So... Ezreal was recalling, I ultyed with Vi the last seccond of his recall, it showed the red line of Vi's ulty (for a second i tought i might end up win enemy base with that ulty) and than it went to cooldown but no effect.

Regards Sir Se7en