As many people have known for a while now, Recall has a small time period near the end of the channel where Recall cannot be interrupted. It's evident that Riot wants this to be a mechanic since it hasn't been removed, but from a design standpoint: Why?
It prevents spaghetti code, and it also helps when you're trying to recall in an area in which enemies know you're trapped in. If it weren't for that grace period, there'd be a lot more frustration when someone steps into a bush at the last moment of your recall.
As there's plenty of instant damagers, if they didn't have that grace period they could use them to interrupt it at the last moment. Which would be almost as tilting as your teammate stepping on a shroom at the last moment and giving the enemy teemo baron and a penta.
