Right now if you use a tc to enchant a reindeer knight but don't use that enchanted card, at the end of the battle you get the enchant card back in your draw deck and not an enchanted reindeer.
This is intentional. Players can't use TCs to pre-enchant spells that are included in the Spellwrighting system.
Why wouldn't you just make spellwritten spells unpre-enchantable and leave the normal spells alone. Or make pre-enchanted spellwritten spells unuseable for pvp. I don't Pvp myself and making changes like this without telling us is just wrong guys, just wrong.