I've just noticed this issue in the beta, and it's a little confusing. From what I can tell, neither the Blue Bead nor Wizard glyph conversion will not work while you are mana burned. However, there are at least two ways to restore mana while mana burned (without curing mana burn): Glowing Guardian's Protection boon, and a Thief drinking a health potion. (Similarly, a Paladin can restore health by killing undead even when he is poisoned.) This seems inconsistent to me - either they should all work, or none of them should work. I personally think they should still work, since the purpose of mana burn is to prevent natural mana regeneration from exploration, while all of the above methods of regeneration are from sources other than exploration. Still, restoring MP while mana burned is very powerful - it gives you a quasi immunity to mana burn, allowing you to attack an enemy that has mana burn without losing any MP - so it might be appropriate to nerf in all circumstances. But as it is right now, you have one item and one class that are both a lot less useful than they could be, and one boon and one class that are a lot stronger, and it seems rather arbitrary to me.