Part of the last update made it so babies no longer wander around after being born/hatched.
While on the surface this sounds like a pretty solid convenience QoL, wandering babies did have it's function.
Attached is a picture of what happens now that babies don't wander. Each and every mosasaur baby is stuck well inside the mother and it's now a nightmare to claim them.
My suggestion would be to only disable wandering after claiming, or to take a look at where babies are spawning from animals that give live-birth.