ue5-authoritative-vs-cosmetic
Authoritative vs. Cosmetic
Presentation in UE5 is allowed to lie. That is its job: animation moves bones, suspension tilts a body, camera shake displaces a view, interpolation smooths a position, and a simulated visual mesh drifts from the logical one. All of that is correct, and all of it happens after the values gameplay should have used.
The failure is reading gameplay truth out of that layer. It produces bugs with a characteristic signature: the error is proportional to how much the decoration is moving, it is invisible when the scene is still, and it cannot be found by debugging the system that appears wrong. A fraction of a degree of cosmetic tilt at the origin becomes a large error at the target, and every hour spent tuning the system that reports the error is wasted, because the error was injected upstream.
The fix is not a code change. It is deciding, per quantity, which representation is authoritative — and then never letting the other one reach a decision.