The buff you received at the lower left corner is your Essence Harvest feat being procced because you got a warp charge after killing the enemy with a brainburst, that’s not Cerebral Lacerations.
Cerebral Lacerations is a 25% damage debuff placed on the enemy, it won’t show up as a buff for you in the lower left corner because its not a self buff.
Try brainbursting a Crusher twice, you’ll see that the second brainburst does more damage than the first.
it never had a hud display and neither do other debuffs placed on enemies in the game, its not a bug. if you feel it should be changed then make a post in the gameplay feedback section
That’s not a bug. It makes no sense to have a buff bar icon for an enemy debuff. How would it communicate to you which enemy is debuffed? That just doesn’t make much sense.