Unsure if this is intended or not, but after the patch Fading Memories is taking a flat 6% of my bard's mana pool to use. The patch notes / AA description say rank 3 should only take 2%. Was looking for clarification on this -- didn't seem to find any other forum posts mentioning this so my apologies if it's already been addressed elsewhere.
I would recommend identifying the server and post it in the bug thread is this is truly happening to you. Rank 3 is correctly taking only 2% mana from me on a real server.
In the bug post you said you're on Lockjaw, which I didn't think had Underfoot open yet (I'm probably wrong). Underfoot is required for rank 3.
Underfoot isn't unlocked, however on my AA screen it is showing me as having ranks 3/3. If it truly is locked to Underfoot, then the AA window is broken. https://ibb.co/sRdbFN0