seems we have found part of the problem. If there is a two or more topics with the same titel, it merges part of it and takes some posts out and makes them info topics. So the problems could have something to do with topics in the same forum that have the same titel.
Also if the user has changed the titel in some posts it seems to cause problems. Because a post from a topic appeared in another topic. And in that post the user had changed the titel. The other posts in the topic were not moved.
Still looking for a solution, so I hope someone could help.
