Are you meaning that it works fine with Full VPN mode enabled?  But it doesn't work with the game item only? If then which part do you encounter this issue?

Yes, thats what I mean.. I wanted my other apps to get internet traffic from my ISP. Cause full vpn mode affects my browsing speed, I was able to play maplestory2 but I cant listen to youtube because the bandwidth is limited in fullvpn mode.

As workaround you should use one of methods at Unsupported Games. And if you want to see it officially at Mudfish, please send me some game packets using Packet Capture with Mudfish link while playing the game with Full VPN mode.

Hi, Maplestory 2 is officially listed at Mudfish. But whenever the item is equipped without full vpn mode the nexon launcher wont let me play because it was detecting the IP of my ISP.

If you can access the nexon launcher with Full VPN mode, I think you can follow Packet Capture with Mudfish link.  Please try to capture some packets for us.