Here’s my thoughts. If it were me, I’d mark the specific area the “variation” sport is, then, once blooming is complete, take cuttings of the new branches emanating from this area once these get about 3” or more long with multiple leaves and put into water out of the sun. Leave two new branches horizontally located, if possible. (You can cut these back to two leaves if needed to keep the outline) Doing this, if the cuttings fail, you still should have the variation on your azalea to try again later.
Excellent idea!!! I am very curious whether the variation sector sport will persist, or if it's a one season fluke. I will mark the branches and observe them again next year (they're really too thin/weak to try and propagate cuttings from yet). If they persist next year, I'll take cuttings per your (nicely detailed) instructions and see if I can produce new plants with this trait.