I think that this thing must me changed, if monolophosaurus use the 2nd and 3rd skill in sequence the damage of the enemy is reduced to zero …the right thing should be (original atk - 50%) -50% so the result would be 25% of the base atk. Instead the game calculates the % to subtract always from the original atk of the Dino and this is why it’s reduced to zero
This is like that also for buffs. I am ok on what are buff / debuff calculated right now.
Btw, when you are facing a monolofosauro in battle, try to counter her with immune dino or dinos with superiority strike or at least DoT dinos since the bleeding start also at 0 damage like facing an invincibile dino.