Yes, I have played around with the session-timers setting in asterisk and it doesn't fix it for all of the situations. Voipo uses some upstream providers with timer issues and does not have anything in place to address the issue. Normally what voipo does is bypass the issue by using a route treatment to go to a different provider, but this happens on quite a few numbers and I can't keep submitting tickets for this.

Another voip provider that does not proxy the audio can still have this issue since the communication bypasses the provider once the call is established. For the provider I have no issues with, they do proxy the audio, but I have zero issues. It could be something else other than the audio proxying that addresses the issue, but I do know that voipo doesn't handle it well.