Monitor wil tell you. Run the targeting filter, lines, call events and ars. It may come back with something like :attempting to target 308-not logged in- no voicemail-no overflow configured busy here-endingcall-
Beep beep beep
Monitor will tell you why the system is doing what it is doing.
We all use it to quickly find out why.
If you can't decipher it, post your trace of the event here. Just the event, not all telephony actions since July
2016: The year death stopped giving a sh*t