[GAMEPLAY] Vi Ult issues

So, I just played Poppy against Vi, in top lane, her vault breaker is properly interrupted by my W, Steadfast Presence, however her Ult behaves erratically and I don't know why.

When I pop W before her ult, she bounces off no problem, when I press it while she is channeling and I see her fist glow and the thing over me or an ally, she flies at me bounces off but I still take the damage (but my allies don't). If she is mid flight she bounces off it then continues flying back at me like she never bounced off in the first place. However, that's only if I am in her path to my ally, the interaction between Vi ult and Poppy W is all kinds of wonky and while it didn't ruin my game persay, it was annoying and unexpected.