How does the rest of the plan look?
I think its just 'shock' from repotting. I have 7 plumeria and 3 of them have just dropped the first of their original leaves. They are trees and they will lose leaves in response to their environment. Since you are in partial shade you wont need as much water, but give it some fertilizer at next watering but do so lightly. What type of soil did you plant in and how is the drainage for that clay pot? You dont want any excess water or moisture at the bottom.
