Listening port reported closed, but slsk still works, should I care?

[random random]

I'm trying linux mint as my daily driver, and it works fine. I'm also gladly surprised it has nicotine+, a client for soulseek that works perfectly.

But the thing is, when I set the native firewall on, nicotine logs shows that port-forwarding isn't working, and when I turn it off, it shows that the external port was successfully forwarded. 

And now what seems a bit strange: when I run the port test, it says CLOSED, no matter the firewall state (this happens on my windows machines too). And the strangest: it works anyway, I receive queries, upload files, I can search and download normally too.

So, it is technically a bit frustrating not knowing why something works, but I also feel relieved by not having to troubleshoot something obscure once again. 

I'm posting just as out of curiosity, not necessarily an issue I have to solve. Maybe a guess about what is happening.

[Nicollas Krijanovsky]

Yeah I have the same issue here(Win 10 machine). Its a bit frustrating because I don't wanna be using slsk the wrong way, downloading everything and not sharing with anyone. I have been opening and closing ports with my AV, Firewall, and using CMD and Powershell commands but nothing seem to change the Closed Status of my port. 
Just like you slsk works like a charm for me, bit it bugs me out not knowing for sure if I am really sharing.

If anyone could shed some light on the situation would be greatly appreciated.