Water vapor in an insulated smoker just from the meat and no water in the pan will reflect back all light outside the top vent and not penetrate smoke so you see white. Depending if your at the beginning of the smoke or stalled with juices on the meat surface and what is vaporizing in the pan in a very humid environment. With thin blue smoke the longer wave lengths on the red side of the spectrum pass through the smoke but the shorter wave lengths on the blue side do not and are reflected back to your eyes, making water, the sky and glaciers blue etc. Like a rainbow, it's more prevalent when the source of light is behind you and your looking at the rainbow or smoke. Stick burners that are not insulated take much more air and fuel to get the same temp as an insul elec smoker will. This makes it easier to reveal TBS because the higher air flow can handle the water vapor unless your smoldering too much wood in the stick burner then it's white.
The cigarette scenario whereby it's smoldering TBS sitting in an ash tray then take a drag that stokes the cigarette will produce white smoke in itself from volume like overloading a smoker with fuel but will also be white because the cigarette smoke is humidified with water vapor every time you exhale.
Then the opposite with twilight at sunrise and sunset where the light comes from a distance below the horizon so you see the longer red wave lengths that can pass through the particulates in the atmosphere and the blue light has been scattered and not seen.
That's why the window in a smoker gives you the true density of smoke. Also, if the smoke exiting looks whitish and quickly dissipates, then that is water vapor vs. lingering heavy white cloud smoke.
From this angle where the light source is behind me this TBS pops but from the opposite side inside my house not as much and a light white smoke coming out of the humid smoker dissipates quickly being water vapor. I let the pellets flame and go out and fan them to ignite then go out and repeat till a decent ember pile forms. I let the
Amnps sit for a minute and place it where you want it.