The final option for the enchanter event seems a bit strange. The event affects a melee unit, but the final option gives the unit enchantment I and free adept unit. The free enchantment promotion is completely worthless for the melee unit. If channeling I was also gifted to the unit, it would be able to enchant blade (which seems to be the point of the event).

It is a known and reported bug. No events that give a promotion work quite right at the moment.