I think it actually is a crestate form of growth, Gigi. Some succulents grow crests, and do just fine. I am not sure a plumeria will do so. I have a feeling that there will be little if any growth, few if any leaves, and no inflo. That's simply a wasted tip and if I ever see this happen (it hasn't happened in 30 years, so probably won't), I'll cut half that stem off and hope for normal tip growth.
