Missed call notifications: Internal calls regarded as external calls - how to distinguish?

Even though we have turned off missed call notifications from internal, we get missed call notifications also when an internal extension has called.
When we tried turning off external missed call notifications, it worked.

So, how does Freepbx resp. the “Missed call notifications” module distinguish between internal and external calls?
Context in the advanced extensions settings is set to “from-internal” (default).

I’m not aware of a similar report, so we would need to see a full call trace of the reported behavior. See this page:

freepbx pastebin is down while it’s being rebuilt, so share via pastebin.com or some other similar service.