Building an enclave or any associated building that increases essence does not update the currently maintained spell, nor does acquiring new shards update the current effect. This makes maintaining spells (both city and unit) a frustrating experience.
It is also extremely gamey to say cast enchanted hammers, build an enclave, dispel enchanted hammers, recast it, then cast all the other enchantments to save mana rather than simply making the decision on what is needed at the time.
