i've see my dinos like "dissapearing", you can't see them but they are on the maewing, eject babys and press "J" (follow all) and leave render distance
the babys still full of bugs like stuck on invisible tails, ruberbanding and visual bugs since years ago
also try to leave the maewing far away from walls, ceillings or mountains, they can get stuck even if they are more small than you can see