Po and Tai Lung defend Kai, yes it's usually the other way around, but when they are in the jade palace, Kai gets occasional scolding from Shifu or Tigress (mostly Tigress) and that's when Po and Tai interfere, when Shifu scolds Kai , Tai Lung is the one who enters the argument most often, and occasionally Po, clearly in a respectful manner, but every time Tigress comes to scold Kai, they both enter the argument in a more aggressive manner. Kai doesn't really care what they say and usually ignores them and leaves them talking to themselves, but when Po and Tai Lung get involved, he stays and smiles from time to time in a teasing manner (this happens especially when this tigress)
various concept pieces for kung fu panda 1! a whole lot of crane, early versions of the furious five, some sequences for the original envisioned fight between po and tai lung in the 'vault of heroes' beneath the jade palace
can find more here https://www.artstation.com/artwork/29n0qY