I have a few bud-builders in my garden. Firestorm usually does it and I've discovered that Orange Aglow does it too( I really like this one, It's been blooming since late June!!!). I think 1 or 2 of my firestorm babies have inherited this trait. I'll know for sure if they do it next year as well. I really like this in a plant.
Firestorm
Orange Aglow