Hi, Its certainly not a bug or issue with the firmware if you're running the latest 'FW ver.: RUT9XX_R_00.06.05.3'
Are you doing the port forwards via CLI or GUI?
My recommendation would be to;
- Default the RUT back to factory defaults, setup the WAN again.
- Make sure that you're using the correct APN for your service provider to obtain a Public ip address
- Then setup the port forward in the GUI Network --> Firewall, Port Forwarding.
- Make sure that 'enabled' on the forward rule is ticked. Hit Save and wait for it to write the config.
- Click 'Edit' on the port froward line you just did, then scroll down to the bottom and check 'Enabled NAT Loopback' (just incase you're testing the port forward from the same WAN)
Let me know how you get on