Recently, on some selected torrents, I have witnessed what appears to be some sort of botnet connecting to seeds. I have these suspicions because all of the bots have used the same port, and they do not transfer any data (incoming or outgoing) and they don't set any flags - they also indefinitely remain (in this case) at a fixed percentage. I think that Tixati should have an option to discard peers that don't send/receive any data, or that don't increment their piece count even when they are accepting data (perhaps a small heuristic scan that can be run on a separate thread every X seconds to minimize CPU usage).

Here is an image showing the problem: (pic removed by Mod and sent to Devs) (the peers remain like this forever - or at least until they are ignored or blocked)
I can provide the magnet link of the torrent if required (it's a politically sensitive torrent - perhaps it's a government organized IP scraper, who knows).

If they are remaining at a fixed percentage isn't it possible they are people with partial seeds?

It is unlikely if all of them use the same port.