Start Not Sync'd

On Private MP lobbies some players are not sync’d properly in the start procedure and start the race when others are already moving on the grid, which causes chaos, accidents and frustration.
This used to happen when the game came out and is still happening. 2 out of 12 in tonight’s lobby in Rio. When not sync’d the player doesn’t get the countdown, it just starts but other cars are already moving and everything appears normal to them other than the affected cars not starting and being stuck on the grid.