I agree that there are two possibilities, with one being that the sweat off the meat is creating steam, not white smoke, which does look like bad smoke (but, smells different). It could also be that the fire gets a little wonky when you add the meat, but, that clears up within 30 minutes when it happens. I never worry about that.
If the larger meats are coming out fine, then the fire is clean. Smaller meats require a little different care, as they take smoke more. I cut back on wood late in the cook for smaller meats. Note that meat can take smoke for the entire cook, ribs, for instance, can get overly smoky to some, if you smoke through the entire cook.
Whip It Off, Chambers!
"perhaps...but then again...maybe not..."