The Call History log will be all telling here, it should confirm what you are seeing, i.e., show an incoming call from SPx ring Ph1 and/or Ph2.
Call History: Not viewable via the ObiTalk Portal. You have to access via the Web Server-Based Local Configuration (also called The OBi Device Management Web Page also called direct IP address interface),
How to link.
For determining which phone rings, the controlling fields are under Voice Services > SPx Service > X_InboundCallRoute. For this you need to go into Expert Mode in the ObiTalk portal. However, these *should be* set correctly via the non-export mode wizard when you setup during GV and the two CCs.
Another point, are you using CC's new extensions, or two separate CC DID numbers? CC Extensions use this format for your 1777 CC number: 17771112222999 where 17771112222 is your main CC number (note not your DID number) and 999 is the extension.
The Obi202 field for this is found at SIP Credentials > AuthUserName in the Obi SPx Service web page. CC has an updated (for extensions) explanation
here, scroll down to ParameterName > AuthUserName.