Moving will be made to interrupt spellcasting at a point in time...

[Tetsaru]

I don't like the idea of moving interrupting spellcasting either. If players need to cancel their spellcasting, there should be some sort of button command or UI icon to click to do it instead, and without causing any animation lock, at that.

Twitch? What is this?

I'm pretty sure they mean games that involve split-second responses in terms of movement and executing actions. Really, I think the Ifrit fight has some twitch elements.

Either that, or they mean Twitch from League of Legends, lol...