if you compare
root rss feed: http://xfsoccer.me/forums/-/index.rss
1st 2 posts are from 1 forum and another posts are from a 2nd forum
1st forum: http://xfsoccer.me/forums/talks-about-xfsoccer.10/index.rss
2nd forum: http://xfsoccer.me/forums/talking-about-matches.9/index.rss
you will see that in /-/index.rss, post from same forum have exactly datetime stamps.
started wondering today why old threads are posted again onto my facebook page via rss graffiti
using xf 1.2.1