I have found th solution for the port forwarding problem in the XFI app
Simply disable under More/MyServices/ The XFI advanced security options
Looks like it works only if the port forwarding is added from comcast service and not through the XFI app
So, if i add a port from the xfi this port won't open
If comcast team add a port:
a) if advance security is enabled won't work
b) if advance security is disable will work
It sounds like you've found a work around and not actually solved the problem. If you should be able to add the ports for forwarding using the Xfi app and it doesn't work, then the app has a bug. Does the app have an option to submit a bug report to the developers? Maybe a Comcast agent reading this will open a ticket or contact the app developers for investigation.