The recentchanges page can currently display merge commits, such as "Merge branch 'master' of ssh://git.kitenet.net/srv/git/ikiwiki.info".
It should filter these out somehow, but I'm not sure how to do that.
A merge in general is a commit with two parents, right? But such a merge might be what gitweb calls a "simple merge", that is I think, just a fast-forward. Or it could be a merge that includes manual conflict resolution, and should be shown in recentchanges.
Seems that the problem is that it's calling git-log with the -m option, which makes merges be listed with the diff from the perspective of each parent. I think it would be better to not use that (or possibly to use the -c option instead?). The -m makes it show the merge from the POV of each of the parents. If the -m is left off, none of the changes in the merge are shown, even if it includes changes not in any of the parents (manual conflict resolution). With -c, it seems to show only the unique changes introduced by the merge.