UI lag during Night Shift transition /w external displays - macOS 10.12.4 and 10.12.5 beta

I'm finding the Night Shift day > night transition causes very significant UI lag on our Late '13 Macbook Pros. We're seeing this in 10.12.4 and the 10.12.5 beta.


Has anyone found workaround or is this just an OS bug / performance limitation presently?