sounds like this could be probable for me as well - I haven't taken it out to check but going off of memory that I prioritized the mitre cut of the red tube to match the radius / angle of the inner skimmer tube. I had to back the tube off a tad so it wasn't completely tight - will confirm later

the skimmer appeared as if it was going to work properly after I had taken it all apart. I not have the riser tube almost completely closed, while sitting in a steady 8" of water. I've had this skimmer running twice before without this concern. it almost seems as if the bubbles I'm getting are different, almost as if anything that spills over into the collection cup is watered down, rather than thick and dark (as before)

Mine started overflowing about a week ago. I pulled the pump head, unscrewed the venturi from the front. Gave it all a vinegar soak and scrub with an old toothbrush and it started working normally as before. I think the Omegas are very sensitive that way but periodic cleaning should help. Hopefully you can sort yours out too as mine skims a nice dark smelly soup 99.9% of the time.