This is there to explain that the physics engines convert your rotation to quaternions so don’t use .rotation after setting a physics impostor. I do agree however that you can understand this sentence a bit differently 
This is certainly a bug, and it seems like the extent size change is the way to go. There was a reason why we decided to use extendSizeWorld, so I will have to see when what should be used. The logic is clear thou 
Want to report an issue on github so we can follow this? Link this thread as well when filing it.