I wish I could tell you but honestly, I don't really know. That was before I was into having and maintaining a guide, and I never actually got to own a Pumperilla pre-nerf just because it was nerfed on day 1 on it coming out.
Sin and I honestly believe that if a nerf was going to happen, it would have already happened.
They could have been re-released in the After School Life CI. In the GCD I saw people saying they pulled a Purrstachio and a Bubblegum Cria, so perhaps it's possible the Monthly CIs have a chance to re-release kin now? I think that's the case with Pumpae, but for Cereus it looks more like people just selling it because they don't want it anymore. I'm only basing this off the levels of all the listings beween the two, it might not be true though.
Sorry if that's not really helpful, that's just my observation, and opinion on the matter of what it might be.
Hi. I got this from the mini ci back in the end of March, the Chocolate Bunny.
After they pulled it from the shop in early April, It seems to go back on sale and very rarely for maybe less than 24 hours as apposed to full time when it was out for Easter.
Hope that helps. `w`