If Theurgists are having trouble completing your level 48 Life spell quest, you must have access to Oakheart in the Jade Palace.
To access Oakheart in the Jade Palace, you must complete these quests, in this order. A lot of these quests are the same side quests that you need to complete for the “Wizard Tours” quest or Obsidian Chests quest to get access to the one chest in MooShu. You may have already completed them prior to receiving the quest for your level 48 spell and should therefore be able to reach Oakheart in the Jade Palace directly.
If you HAVE NOT completed these quests in your adventures in the spiral, you will need to do so in order to reach Oakheart in the Jade Palace.
Cave of Solitude 1. I’m Cursed (from Mossback) 2. Rock On (from Mossback)
Kishibe Village 1. Wear Your Gloves (from Mossback)