Both of said bosses suffer from a BS bug that their frontal cleaves hit/kill you even if you aren’t infront of em, may it to either of their sides or behind em, this is still happening and unadressed.
Abilities in question are: Smash from Ingvar the Plunderer and Pound from Anub’arak
In-game bugs need to be reported via the ‘Submit feedback or bug report’ button in the game’s Support menu. It’s the button with a picture of Anub’arak on it.