Casting Astral Infusion Can Be Delayed [GAMEPLAY]

When playing Soraka with 40% cooldown reduction, Astral Infusion seems to not cast immediately after coming off of cooldown. If I input a movement command after my initial cast, the following cast functions normally. I have tried this with other configurations (no Aery, different cooldown reduction items, auto-refreshing cooldowns, normal cast mode, etc.) and the results appear to be similar, but I do not recall experiencing this outside of the practice tool. Is this intended behaviour?