@Nefarion: This is a bug, for sure. Unfortunatelly, to fix this bug I need to revamp visibility management rules and that will take some time. Hope that will do it soon.
It started working the other day, then stopped again. I managed to fix it..
The checks you make to UnitPowerType in Provider_DruidMana.lua are causing the issue, and commenting them all out fixes it.
By the way, looking at your code, it looks like you tried to hide the outline when in caster form, which wasn't working anyway.