It’s a bug on Blizzard’s end with two pets (the Treasure Goblin and Dread Hatchling). While they are technically showing in the Armory, they are not being returned on import for some reason. So to create a workaround, we’ve temporarily flagged them as pets that can be added manually.
You can add them by going to “Update Collection” and scrolling down where you’ll see an option to add them. They will be added a level 1 pet, but anyone that had imported before should still keep the level shown in their last import. Until this bug is fixed on Blizzard's end, however, their levels will not increase.