We have used wet pellets before without problems (we washed them)
So I'm not certain what the impact moisture has?
But what we did notice about bubbling is that MG94 produces Gas somewhere above 200°C so bubbles form inside from the gas itself (even desert dried pelllets produce gas bubbles) which then twists and merges into the structure as it's extruded creating a weak filament with air pockets.
Last year, the temperature sensor was dislodged so our filament was heating up to 250 degrees C causing them to be very brittle with lots of evaporated plastic air pockets, We solved this by wedging the sensor onto the heater itself, instead of the notch at the nipple/nozzle
We also pre-heat the nozzles and letting it sit for around 5 minutes at 200 degrees C to let all the air escape and the filament melt properly then the filament that came out was nice and smooth, at least for a while...
after that it depends on extrusion temperature. Mentioned somethere else on this forum. 235 deg C on MG94 pellets creates rough filament, but smooth with PA747 pellets.. so it depends on your pellets. I personally prefer PA747 over MG94 at the moment due to high temperature extrusion ability.
hope it helps