hey, i was looking thru the trinket vendor today and i saw a trinket called "The burrower's shield" i bought it just for the hell of it. i went to SM using it and ive noticed that i am not receiving any damage from the mobs. i took off the trinket and started receiving dmg again. i knew it was the trinket thats bugged.
The Burrower's Shell - Item - World of Warcraft
link to the trinket