I have always had great winds before I tried Huel, and in the first months I found that they decreased both in magnitude and frequency.
Lately I have been experiencing a comeback, even though I have switched to the unflavoured version since it’s available. So this would likely rule out the sweetener causing it. I also think that this increase could either be the result of the slight increase in the portions (from 100g to 125g poweder with about 5-600ml water) or a change in the exact components in Huel. @Julian mentioned actually that there could be a slight variation in the source of the components