[Mister Moo]

Old farts are failing with this stem juncture at every juncture. Here's my shot.

I had one pipe - a good pipe at that - with an internal distortion inside the pipestem airway. Mostly it blocked a pipecleaner yet I could blow air through it. Sometimes I could work a pipecleaner through it (or past it) by bending the end of the pipecleaner a few degrees and twisting it, pushing and probing, until it found the passage and passed; other times a pipecleaner would get blocked, pop through and then drag on the way out leaving a wad of cotton caught in the airway. Then one day after dozens of tries the irregularity broke loose (I never saw what it was), a wad of cotton blew out and all was well.

Conclusion is same as above whatever the problem is - call the seller and ask what's the deal and/or send it back if that's possible. There is no good reason for an airway to prevent passage of a pipecleaner unless it has an internal filter (and, presumably, a way to remove it).