Breedable animals can be breeded with their parents.
To try this, take two cows, make them do a baby, make this baby grow up by feeding it or waiting and then try to breed it with one of the parents.
A way to fix this would be to put a new NBT tag for breedable animals called "Banned UUIDs" and upon creation of the baby automatically put the parent's UUIDs in this banned tag.
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