While I have yet to experience the Great Flatulence of Huel, I just experienced my first diarrhea-esque Huel poop. 
Pleas congratulate me on this great achievement!
But for real though, it made me a bit uneasy about consuming more Huel. Does it get better over the time or do we sacrifice proper digestion for convenience, money savings and health 
it gets better. if i remember correctly, you’re consuming a LOT more fiber than usual (probably). thus, things “move” a bit faster. keep it up, and your body will adjust. everything will keep moving, but, less “quality phone time” is a good thing, right?
What @shaunfather said is correct! Huel is higher in fiber than most food we typically eat. Because Huel is high in fiber sometimes this can lead to gas/an upset stomach. Generally this settles once the gut gets used to the dietary change.
It took me getting through my first two bags of Huel to get used to it. I have 7-8 scoops of Huel a day now and I don’t feel any different than when I wasn’t on Huel any more. Bowel movements are normal all around now. But I have noticed that if I skip Huel for a day or two, then my it takes a day to readjust again. I’m pretty sure its more than just the fiber content though. Surely something about eating powdered food has something to do with it.
The only change from a more traditional food is the lack of chewing which starts the breakdown of solid food to increase the surface area and there’s also one enzyme, salivary amylase, which breaks down the starch into maltose.
With liquid diets, this has already been done for you and salivary amylase has very little effect on total starch digestion - it merely kick starts carb digestion as, in the stomach, it itself is broken down (remember, enzymes are proteins). It’s sister enzyme pancreatic amylase which acts in the intestines has a more pronounced effect where even previously solid food is in liquid form called chyme.
So essentially, after you’ve swallowed your Huel the body treats it the same as any other food, there aren’t any major differences.