I live in Central Florida, and my potted plumeria bloomed for the first time in December 2017, this past Christmas. It is still producing blooms now in January 2018. I brought the plant indoors about 3 weeks ago, since we were having very cold weather, and a couple of hard freezes and frost (you should see my areca palms now, ugh!) Anyway, the plumeria leaves are starting to yellow and fall off, yet it still pushing out blooms. I have it in a south-facing window, where it gets lots of light and warmth during the day. I've been gently watering it once a week, when I give my other indoor houseplants a drink. I will get it back outside by mid-March, or sooner if temperatures cooperate and we get our normal warm winter weather. Is it weird to have blooms in the winter? Do I clip off the leaves? Or leave the tree alone and let nature take its course?
This is not strange. It will be ok, but I would let nature take its course. I would not clip the plant until you get ready to put it back out. It will likely survive. Many plants that are meant to be outdoors will struggle when brought indoors. Just be patient and keep care like you would normally. Here is an article for more information on their care: https://www.gardeningknowhow.com/ornamental/flowers/plumeria/growing-plumeria.htm