Has anyone experienced the following odd behavior in a Sheaffer Triumph plunger-filler? Usually, one gets into the barrel by unscrewing the Triumph nib. Believe it or not, there are those that come apart at a joint directly under the barrel's thread ring (I'm not talking about the kind with clear tubes inside the barrel), yielding three parts: the nib, the barrel, and, wonder of wonders, a "section" collar with a flange on it that friction fits into the barrel. I discovered this joint in pens that seemed to leak from beneath the thread ring. The odd thing is that the ONLY Triumphs that have come apart on me in this way are BLACK striped ones, not carmine, not pearl gray, not emerald, nor golden brown. WHY!? Is there any way of repairing it. Don't tell me shellac! This so far has not proved sturdy enough for the significant stress on the critical part of the barrel.
I will be at the DC show if you have an extended answer AND I'll be wearing a name tag "Gerry Berg".

Cheers,
Gerry