Mythic Haste states:
Affected creatures gain an additional move action each round.
The rules for casting spells state:
A spell that takes 1 round to cast is a full-round action. It comes into effect just before the beginning of your turn in the round after you began casting the spell. You then act normally after the spell is completed.
If I cast a 1 round spell before using my move action, does the spell finish early?