There’s definitely problems with billboard mode because the viewMatrix is not updated.
We deduce the projectionMatrix from Mapbox coordinates and we freeze it (line 68 here)…But the camera position in fact is still (0,0,0), we overrided the projection matrix to fit the mapbox world, but from the billboard pov, camera is still at the center…
I tried to solve this problem but did not found the time to achieve it :p. If we could deduce the new camera position from the mapbox world matrix it will make the job but it’s complicated to transpose the viewMatrix.
I don’t work on mapbox anymore but new versions now come with a freeCamera support and the code should contains all the info to make a better transposition of the mapbox camera to the babylon world.