Sion Q Indicator Bug [GAMEPLAY]

I was playing tristana on red side against a sion support, and he chilling in the bush to use his q without me seeing him (like most typical sions do to try and cheese anyone). the ward we had in the bush died and I went up to place it quickly to dodge his oncoming q. However, the indicator showed one way, but as I began to move up toward my tower it changed more forward and I ended up walking straight into the middle of the q, getting me dangerously low. It was kinda tilting cause I felt like I could have dodged it if the graphic hadn't shifted like that. went through the replay and it didn't show, as well as my support didn't see anything strange, but I know it happened :/