A post that I just put up — this one — won’t generate a working autolink to Twitter. If I manually put in the link, it works. But not if it’s generated by that widget. And all the other posts I check worked, and this post worked just now, so it’s only that one post.
Weird. Very, very weird.
Looks like there’s some weird character(s) in there that get escaped to %EF%BB%BF and vanishes in rendering.
.
Some googling indicates that it’s a UTF-8 Byte Order Mark, so it’s basically invisible. Unicode’s awful for this sort of thing, both for having zillions of weird, arbitrary edge cases and for being a complete hash of not-quite-correct userspace implementations.
Weird.
My guess is that somehow you stuck the Unicode BOM in there and that the Twitter widget saw that–note it’s %EF%BB%BF–and url-encoded the % sign to %25–you can actually see that if you view source the Faction etc., post; the generated URL has %25EF%25BB%25BF in it, and multiple rounds of URL encoding produces gibberish.
If you can redo the post and get the Unicode out of the title (I don’t know how WordPress works; you may have to delete the post and make a new one?) it will probably fix your tweet.