Buffet node states that “next buff is immediately consumed and defender regenerates x% health”. What is happening is that ALL buffs are consumed at the start of the fight.
In the attached video, Corvus should walk out with 3 buffs: 2 stacks of cruelty and true strike (or true damage). All 3 buffs are consumed instead of just one.
https://youtu.be/8c9nwvvrlw4