I seriously doubt that whatever is bubbled at the zoo is anything other than Rose Quartzes, Pink Diamond obviously wasn't around to poof them because she had faked her own shattering and Blue and Yellow were under the impression that there were Rose Quartz soldiers in those bubbles and there's no one else who could have ordered them to be bubbled? Blue Diamond wanted them to be preserved, and Yellow complained about it. Didn't you watch that episode at all, or... ?