Bug Cast animation

Hey there! I have a game where a mage casts a fireball, and the fireball had to be casted only if animation is performed, and when the character isn’t moving. But the thing is, whenever I the char stops walking, there is a little gap in like 0.5 seconds, in which I can cast a fireball without the animation of the cast. It doesn’t have to be like that. Btw, after this gap of 0.5 seconds is gone, the fireball is casted properly