After today's patch I've noticed that whenever I cast Mantra of Healing I got a shimmering bubble around me and my followers, at first I took it simply as an added effect to show that I have the Sustenance rune equipped, but at one point I was hit by a fireball just after using the Mantra and the damage was absorbed which I have not experienced before, leading me to the conclusion that my Mantra somehow did it. However, the description does not state any damage absorption nor do I even have access to the rune that actually adds a shield.
So is this a bug? or a new effect that the tooltip hasn't been updated with?