This also causes tall animals' baby variants (such as cows / sheep, not pigs / chickens) to suffocate when directly underneath a solid block.

(the baby cow is taking damage here)

What's making you think this is Abnormals Core's fault? I can't reproduce this with just Abnormals Core or in a small modpack.

Not a great reason--it's more likely an issue with Crucial 2.

((I took out every mod in the pack minus this one, and the issue remained, so I assumed Abnormals Core was the cause.
However the issue remained even with no mods in the pack, which I assumed wasn't possible until now. hm.))