Currently, if you play Ashe on PC and have higher than 60 fps, the aim down site (ADS) animation can look choppy or "stepped". There is no lag going on. The ADS still happens at the correct speed. But the animation looks can feel a bit off.
In an upcoming patch, the ADS is smoothed out regardless of how high your fps is and should feel much better.
Unfortunately, right now, the patch that it is fixed in is 1.32 (1.31 is on the PTR right now). We're looking into pulling the fix forward but it's unlikely. It's a lot of code and needs a fair amount of testing so we don't want to rush it and risk breaking something else.
Apologies for the issue.