-snip-EDIT:
My router also has UPnP enabled and I've tryed to check the "map ports with UPnP" in the GUI, on options, without any result.
So, router and node seem to be configured correctly; also, enabling UPnP usually works after restarting the node.
I'm guessing that it may have something to do with your ISP.
Check your "
debug.log" file if there's any entry that hints of inbound connection attempts.
It's in the data directory, open it as text.