PEW wrote: I never configured my Tello voicemail, so I don't think the 2 lines are treated differently due to voicemail setting.
Assuming both lines have carrier voicemail with default settings, it is strange your Tello lines apparently behave differently when powered off. To resolve this, you can set up conditional call forwarding to GV or to a number that always rings busy (early media) - eg;
Missed another call, argh! I guess GV is just not reliable. Had the phone set to prefer cellular and the app set with the phone's phone number. The call went to voicemail without ringing my phone. Possible fix: Disassociate phone app of any phone number, set GV to forward to the cell #. So, device could potentially get 2 calls... just like when I had Hangouts and the cell phone both ringing on the same device. Bottom line, seems no improvement... only goal met is for Google to retire Hangouts.