Dave,

What your seeing is a form of mutation (chimeras).
This is rare to see but more common among pigmented flowers that take on this look. I've also heard of the term "color breaks". It's not a virus as some folks may think.
This type of mutation can affect a few flowers of the inflorescence or only one flower. A mutation also known as a "Sport" is just a change in the DNA of the plant.
I've often seen this happen to an Aztec Gold whereas the colors of deep pink or red stretch down the sides of the petals having an splotchy or spotty appearance.
Because plumeria have been hybridized and crossed so much to create such a wide spectrum of beautiful flower types, we will see this happen from time to time.

So you have a kid with freckles! not to worry, just enjoy!
Aloha, Stuart

Could it be Princess Victoria?

Dave, did you lose the tag to that one? I don't know how one differentiates a sport/chimera from a virus, other than maybe observing distorted bark and leaves in addition to distorted blooms in a virus-infected plant.

Does look like PV, Mona. Could also be from heat stress.

My Penang Peach did this last summer, which was another scorcher:

Poor Hawaiian baby was shocked; the splash went all the way through to the back:

Thanks for the responses. I guess anything is possible and heat stress happened for sure this summer I'm sure. I've been eyeing the PV so maybe the plant got wind of that. Now I'm curious to see if any other blooms have the varied color. None opening today yet, but I'll keep you posted.

Way cool Dave! I know it's been exceptionally hot this summer up your way. It makes sense it's heat stress. The plants are sure trying to keep you happy. Peg

Strange things sometimes happen with these plumerias. When I first saw this one I thought it was a virus, but later determined it was caused by rainwater dripping off a crepe myrtle tree onto the plumeria.
{{gwi:1197798}}

Dave,

It looks interesting, i also think it is heat related, but i still think it is beautiful.. MY Princess Victoria hasnt matured enought to have the color break that it should.. I love it!!!

Laura