Outbound Source IP Filtering?

We just got a 200Mbps EDI circuit installed yesterday. When I was testing, it appears Comcast is doing outbound filtering based on source IP. When ISP B is my default route, I can ping both interfaces (Comcast and ISP B). When Comcast is my default route, I can no longer ping ISP B. Has anyone else had this experience? We don't see this with our other EDI circuit.

There's also no PTR records set up for our P2P block, not even the ip-address-static.hfc.comcastbusiness.net ones. It's almost like something was missed during the setup.

Thanks!