My guess is: incomplete combustion. As in some rocket propellant exited the nozzle of the rocket without burning, and then burning or just expanding in atmosphere (instead of under the high pressure engine conditions) where it lacked enough oxygen to burn white like the rest of the exhaust you see.
In short: old rocket shows its age with a slight hiccup. Its not a big deal because this will be its one and only flight.
Yellow/orange smoke puff at like 50 feet?
Is that to signify it armed or something?
My guess is: incomplete combustion. As in some rocket propellant exited the nozzle of the rocket without burning, and then burning or just expanding in atmosphere (instead of under the high pressure engine conditions) where it lacked enough oxygen to burn white like the rest of the exhaust you see.
In short: old rocket shows its age with a slight hiccup. Its not a big deal because this will be its one and only flight.