On Friday, October 11, 2019 at 11:32:14 AM UTC-4, John DeRosa OHM Ω
PS - I got a response from Gary Kammerer who said it was a "restrictor" and
pointed me to a 2012 article from Dave Ellis "Variometer pneumatics – probes,
tubing, restrictors, etc." that seems to point to the restrictor not being
needed.

It certainly could be a restrictor - depends on the ID of the tube.
The length makes me guess its a netto leak.