Minor RSS import don't work, because it thinks, that articles have Title/Body fields multilingual, but they don't and none of rss feed based articles are created. Maybe that fields were multilingual in past and RSS import code wasn't updated to reflect fact, that they are no longer multilingual.
Also RSS feed from Mantis issue tracker are incorrectly imported in case, when issue titles contain quotes in them. In that case issue title is imported only till first quote in it.