When I used PIA I was absolutely unable to seed torrents (though I could still download). Currently I'm using Nord which lets me seed, but aside from that I don't have any particular reason to Stan them.

I never tried too hard to figure out what was going on with PIA though. My contract expired and I just decided to try something else. I assume they got threatened with legal action and negotiated to filter that outgoing traffic, though it could be anything really, including a misconfiguration on my end.