The feasting Allosaurus never cast a shadow on the Diplodocus carcass. The shadow of one Allosaurus actually goes underneath it. And when it lifts up the slab of meat in its mouth, the shadow of the meat seems to be floating on its own.
The Ornitholestes in this episode produce a different sound than in the original series. The sounds used in this special are actually the high-pitched noises that the Dromaeosaur made. The other dinosaurs retained their original sound effects.
The CGI Diplodocus (correctly) has a single claw on each of its front feet, the other four digits ending in stumps lacking claws. But the physical Diplodocus prop has sharp claws on each of its fingers.
During the hunting scene on the salt planes, at around the 18:27 mark, the two Diplodocus tails on the left side of the screen are twisting in the exact same pattern, which in reality would be very unlikely.
The shadow of the first Allosaurus we see eating the Diplodocus is animated badly, since it doesn't come into contact with the large chunk of meat it's pulling around with its mouth. Later, when it is approached by the giant female, the movements of the meat don't correctly correspond to the way the animal drags it.