Hmmm, I have a pellet stove insert. A few years ago, I experimented with trying to make it more efficient so I cemented off some of the holes in the burn pot up around the top and outside edges. My logic was to only let in air that would be burning the pellets, instead of some of that air just carrying heat out with it.
Well guess what.. IN doing so, I starved the combustion process and creosote built up in the cavities behind the stove and in the flex pipe, it would occasionally ignite and the backside of the insert would get dangerously hot to the point that smoke was rolling out from behind it and I nearly melted wiring and motors and whatever else is back there
Yeah, won't do that again
So yeah, wood pellets can definitely produce creosote under the right conditions