Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:5587526.

I found the original duct sends most the air out of the vent directly in front of the 90 degree bend where it turns into a ring. I stuffed a tiny piece of aluminum foil in that vent to test it and instantly stopped my bubbling on one side. I remixed it with a wedge in the way to split the airflow, while allowing the residual turbulence to feed that same primary vent. Excellent print quality with this now. The sleeve on it should be tight enough that you don't need any adhesive, and you should remove it when not in use to avoid warping from lack of air flow. I used PETG. * I added an extended one that is more egg shaped if you are having issues with it being too close to hot end. *