So you're not the only one! I've been seeding as usual as well on my torrents, in fact I seed (upload) more data than download, and still my BTT balance actually went DOWN. And I leave it on for days and weeks too. My BTT actually goes down over time when I check from the torrent wallet itself. Not sure if scam or not, seems real, but I gave up on earning it:)
That sucks. You'll be wasting time and resources without getting anything in return. BTT is more overhyped than anything else. You can thank the TRON Foundation for that. After they've bought BitTorrent, the project has never been the same. It's much better to use an alternative client like qBitorrent or Deluge than the original BitTorrent client. Unless they remove ads and fix the BTT reward model, I don't see BitTorrent going anywhere.
I've seen some people saying that they've earned BTT by seeding torrents, but I take that with much skepticism. These comments could be related to TRON shills/supporters, with the hopes of attracting people into the project. But what matters is concrete results more than anything else. Too bad that BTT canceled its airdrop a while ago. It was basically free money without doing anything in return. All you needed was TRX on your TRON wallet, to earn free BTT along the way. Now that the airdrop is over, there's no reason to buy and "hodl" BTT for the long term. No utility, means no future for the token. Just my opinion