There is an annoying problem with Spectral Shield...
Get in your max mana mode, regen full... now switch to your regular run mode. Your mana is now in overflow.
However if spectral shield fires, it will wipe your overflow, and set mana as max in your run mode.
For me this means loosing 400ma in epic groups if someone scrolls and spectral is up.
It shouldn't reset mana to max if mana > max.