<3 Tessa-chan! <3 Lucifus! ....chotto mate.
I'm not exactly sure why this is happening, but it seems to be pretty widespread.
The "no_peer_id" option is a tracker bandwidth saver, allowing the tracker to trim out extraneous addresses where appropriate.
However, apparently it's also obselete, having been replaced by the somewhat more aggressive "compact" option. I suspect (but haven't browsed the cvs changelogs to confirm) that the latest versions of the mainline client removed the no_peer_id flag entirely, completely replacing them with compact.
I'd also suspect that other clients haven't gotten quite that aggressive with the changes just yet... which would explain why people aren't having trouble when using clients like Azureus and BitComet (which are their own separate codebases). I also suspect that the tracker we're running hasn't implemented that yet, or separates no_peer_id from compact. And the reason BitTornado and ABC work? They're based on mainline, but they're forks of the code, so they are running on a slightly older codebase that doesn't yet completely obselete no_peer_id, only deprecate it.
Of course, that's only my suspicion, based on an extremely minimal amount of research. Your mileage may vary. If you're interested in a discussion thread about that, see This Yahoo! Groups link
I've brought it to the attention of the guy who would be able to find out anything about it. I don't know when he'll get to it, but more likely than not either he'll post something in this thread, or he'll mention something to me and I'll post here, or something like that. We'll see. Meanwhile, maybe a client downgrade or a different client version could be in order.