I’ve noticed that the ideal setup often produces a slower lap time in practice than what the system thinks is not ideal setup. Has anyone else seen this?
If you're talking about practice times. Ideal setup does not translate to ideal performance.
Car status(fresh engine, fixed car), Driver development(primarily talent level) and health(the higher the better at time of practice) often influence how well the driver performs during practice.
For the most part, most drivers don't show their best performance during practices as all they are looking to do is get their suspension, ride height and wings level setup.