This was shown on Adult Swim instead of Nick Jr. because of the birth scene.
Green Puppy pounces on Shelley. Shelley stands up and Blue, who is now Green Puppy's wife, enters. "Bow bow" "You're looking chubby today, Blue". Green Puppy barks. "What's that, Green Puppy?" says Shelley. "Oh, Blue is pregnant! She's gonna become a mom!" Blue puts her paw on the screen to signify she wants to play Blue's Clues. Shortly after, they find a baby with a clue on it. Shelley draws it in her Paint app on her handy-dandy bigPad. They continue searching, and Blue eats some dog food which is strange for Blue. Shelley realizes the bowl has a clue. She draws it in her Paint app. Blue finally points to the rug which has a clue on it. Shelley writes it down in her bigPad. "Oh-oh! Blue is about to give birth!" Blue goes to the rug and poops out her baby. We hear the baby puppy crying. Shelley realizes that Blue had twins, one is teal and has dark blue stripes, and the other is green like Green Puppy and has teal spots. Shelley gently sings the So Long song to the puppy twins, "Tiger" and "Gina", as a lullaby.
This is kind of a nod to animal births. that's all I can say.