I tried to download two spacebattles fanfics:
https://forums.spacebattles.com/thre...#post-14513760
https://forums.spacebattles.com/thre...ssover.277863/
#1 has threadmarks, but unfortunately also has back/forward links which somehow threw this plugin off.
#2 has no threadmarks, and actually indexed just fine off the first page, but ignored the first post which does not link to itself.
I think #1 happens because it somehow triggered "this has no threadmarks, so treat it as an index page" mode, which probably shouldn't happen with a threadmarked post. (I was lazy and copied my current reading position from the address bar into FanFicFare rather than clicking around to the link to the first page.)
#2 I assume is because authors commonly use(d) the first post as an introduction and index, is there some better way of handling this even if it is on the user end? Interestingly I got a very interesting replacement for the first chapter, I'm not at all sure what is up with that.
The resulting EPUBs are attached.