Hi, Check the ownership of the cameras and PB block, it should be same. Also camera blocks and PB block should be on the same grid, not subgrid.

I know this is old but I am also having an issue with this. Doesn't recognize the camera. No subgrids cept of course the wheels themsleves. Suspensions, Camera, remote, Gyro and Camera all owned by me. Works fine on one grid, but a second it does not see the camera and also just flips itself over.

Is it vanilla cameras? Have you tried to recompile the script after placing cameras? Also I never actually tried top mounted camera, if you use such try using regular ones.