When teams create elaborate systems of mutual deception to manage expectations

I've been CTO at this company for three years and my engineering team has gotten really good at estimating how long projects will take but they systematically add padding to everything they tell the product team and everyone knows they're doing it including the product team who now pads their own timelines and we're all lying to each other with good intentions. Our roadmap is meaningless because it's built on layers of protective dishonesty.