players and minecarts are being rendered at the wrong spot in MP

When riding a track the player is still being rendered at the starting spot in sitting pose for other players. Until now I have been observing this when the track was longer than (say) 10 chunks. But with a new track at high altitude I am observing this also on shorter tracks. I even saw the cart once driving UNDER the track.

Okay its a duplicate of MC-1291 added my additional observations as comment there.