There’s way too much hype over VPN Providers, but do not forget, you are routing all your traffic through their servers
As a general advice, if a VPN provider keeps logs of your activity, does not allow you to pay with crypto, and generally spends way too much on youtube ads is probably not an ideal choice.
Do not follow any advice/recommendation blindly, do your own research on which one offers the best service for your own needs.
I ask because I am on several private trackers and haven’t had issues downloading or seeding using mullvad. By what you explained, it shouldn’t be working…
I might be wrong, but I think port forwarding is working for already set up ones till 1st July. Or maybe you have a leaking port through uPnP? Again, just possibilities, not sure. Or maybe you’ve just been lucky and encountered people with open ports.