My aggregator's RSS items have a <link> tag in them with the link from which tixati should download the torrent. This link points to the aggregator and allows it to flag the torrent as having been downloaded.

But the items also have the "original" torrent link direct to the source site in <guid> tag, or sometimes as part of <description> tag. Tixati usually ignores these, but every now and then it loads them instead of the one in <link> tag. I think it is when they end with ".torrent" suffix. It should not be doing this.

I don't want to break compatibility with some weird RSS feeds that don't have <link>, so it's OK to search for links outside the <link> tag if that is missing. But I think they should never be prioritized over the <link> tag if it is present. It breaks my use of the aggregator by leaving a lot of torrents unmarked even though I've downloaded them.

I suggest you to include a completely anonymized example of the RSS file, leaving only 1-2 torrent items with all their data obfuscated.
https://www.bittorrent.org/beps/bep_0036.html  you can read this document yourself too and forward to admins if something is off. I wonder if it's a Tixati bug or the server sometimes returns weird data.