asterisk users - Jul 2016 - Some SIP OPTIONS packages seem to be ignored by the peer

Hello!

Sometimes, I can see here the following scene:

Asterisk sends 11 SIP OPTIONS-packages (qualify=120) and they are all
ignored by the peers - but the 12. package is answered immediately as
expected (I'm sure there is no network related problem).

I can see this on trunks via Internet and locally with extensions - no
matter if it is via pjsip or traditional sip module.

What's the difference between the 11 packages and the 12. package?
It's the branch, tag and Call-ID.
The 11 packages before all do have the same branch, tag and Call-ID. The
12. package changes them.

Looks like some of these values are ignored by the peers. But why? Are
they broken?



Thanks,
kind regards,
Michael