After renaming the physics-line in the .ini, the layout itselfworks fine and AI behaves very well...but the F3-camera doesn't follow the car and doesn't switch. And yes, i DID read the last comment and your response to it, but i've seen several other maps, where the F3-cam is working with 2way-traffic...so there MUST be a fix to that...still a very neat addition to FATalfie's track :-)
https://www.racedepartment.com/downloads/f3-cams-for-traffic-layouts.31471/
In those there is some flickering and seemingly random switching between cameras - can't be avoided because the F3 view follows the position of the center if gravity of the selected car and it switches direction according to what lane is closest. In 2-way inevitably there is alternating between the lanes. The least flicker is seen when F3 follows a car with AI. So try to select AI car for the track side camera views in replay and from the pits.