Mystical Weapon Crystals / Tavernmaid quest line

I saved 3 legendary weapon crystals in my vault to use this season (they are still labeled as mystical weapon crystals), but they aren't a valid crafting resource any longer due to the change to "forging crystals". Is there a way to convert them?

I have the Tavernmaid quest active, made sure of this, and have fished up the tankard 3 times, it still says 0/1 have not found.