What, in the world, is a violation of causal faithfulness?

@misc{ pirsa_PIRSA:24090115,
  doi = {10.48660/24090115},
  url = {https://pirsa.org/24090115},
  author = {Fraser, Patrick},
  keywords = {Quantum Foundations, Quantum Information},
  language = {en},
  title = {What, in the world, is a violation of causal faithfulness?},
  publisher = {Perimeter Institute},
  year = {2024},
  month = {sep},
  note = {PIRSA:24090115 see, \url{https://pirsa.org}}
}