Smokey at low temp

Morning all - have only owned my ys640s for a week and already love it with multiple successful cooks.
Today I am trying salmon at 165 using cherry pellets. This is my first very low temp cook and I noticed the Yoder was blowing a lot of white smoke.
I shut it down and checked the firebox - all looked good. I restarted and let it come up to 350, and now working it’s way back down to my desired temp.
I rationalised that starting at 165 is too low, and that combustion was not efficient. Is this a thing? Do I have to bring it up before taking it back down?
Thanks in advance from a novice.
Today I am trying salmon at 165 using cherry pellets. This is my first very low temp cook and I noticed the Yoder was blowing a lot of white smoke.
I shut it down and checked the firebox - all looked good. I restarted and let it come up to 350, and now working it’s way back down to my desired temp.
I rationalised that starting at 165 is too low, and that combustion was not efficient. Is this a thing? Do I have to bring it up before taking it back down?
Thanks in advance from a novice.