If anyone has a fix for this, would be grateful for suggestions.
Issue description/steps taken:
1. Factory reset; device deleted at ObiTALK.
2. Obi2182 registered on ObiTALK.
3. Google Voice (GV) account added successfully.
4. Inbound and outbound calls via GV successful.
5. The unit sat idle overnight.
6. Tested again for inbound outbound calls via GV this morning: successful.
7. Added two Asterisk-type IP PBX registrations.
8. GV registration failed.
Conclusions:
1. Since GV by itself was both configured and stable for several hours, the topology of the local subnet and the firewall settings (Sonicwall) were not shown to interfere with GV.
2. BUT - this device with both IP PBX SIP registrations AND a GV account resulted in the GV registration failing. Currently, the ObiTALK dashboard shows for GV "Connecting to 0.0.0.0" while both IP PBX accounts show "Registered". On the Obi2182 device, selecting the GV line produces a "Call Error The requested service is not available at the moment".
With thanks in advance for your thoughts!
Update: Obihai support appears to have solved this by changing settings for which I have no visibility. If I learn what steps they've taken, I will pass it along here.
Turns out the problem arose from the firmware version. My unit was showing 6.2.3 (Build: 4860.1311); Obihai support pushed a new build with the same number that cleared the problem. If you're having this issue (GV failure in a deployment with IP PBX SIP registrations) I supposed the best bet is to contact Obihai tech support.