HI Rcroberts. Bridge mode can be enabled on devices that does not have Static IP assignments or devices that are utilizing public or private WiFi (CISCO DPC 3939 only) as WiFi functionality requires that DHCP is enabled. As your device has private WiFi enabled, placing it in bridge mode will disable the wireless functionality. If you have no plans to use the gateway for wireless networking, we can make the change at your direction.
You can verify if your Comcast Router has been placed in <true bridge mode> by verifying the address of your connected device. Bridged devices pass the public IP Address directly to the router or PC. Since Comcast uses the 10.1.10.X as the default LAN DHCP your device should NOT have an IP address that falls within that range.