Please post a link to your forum and the feeds where you are seeing this behaviour.
http://www.strapontins.org/forum/rss/topics
the topics “”Nouvel header et footer :p” or “”Serveur Jabber im.strapontins.org” for example, are empty in this feed.
bye
i think there is a problem with post they are modified.
I just get 404 errors when I try to retrieve your feeds using curl.
I suspect it has something to do with a bad translation string. Try switching your forum to english to test if that fixes it, if so then it is a problem with the language file you are using.
It also may be a problem with the date or time format in your settings.