Yes, I think this is not unusual.
I've seen the same behavior on OS repos and corporate bug boards.
Gatekeeping behavior.
Discussion
I was employed as a software tester once and a woman who didn't like me sat on the bug board and everything I submitted was immediately closed at the next meeting as "not reproduceable". Within a couple of weeks a customer would inevitably find and report it and it'd get immediately corrected.
One of the developers thought I was being paranoid and sat down to have me write up a report of a bug he'd found and when it was closed, he threw a fit, but she just kept doing it until I willingly changed departments.
Corporate software is one thing, but an open-source VoIP library is quite another. If the maintainers don't understand why using different UDP sockets for sending and receiving won't work if the client is behind several NATs and they don't want to accept the proposal of, like, three people to fix it with the patch being just two edits within one file...
Just checked - they finally did what was necessary in v2.0 though. I wonder who (or what) persuaded them to make that extremely difficult two-line change.
It just had to be the right person suggesting the change. Most repos are like that. They exist to facilitate gatekeeping.
They're a quasi-corporate structure. A code central committee.