When I actualise the feed http://www.pravdareport.com/export.xml, FreshRSS is not retrieving all articles.

I have checked the validity of the feed:
http://validator.w3.org/feed/check.cgi?url=http%3A%2F%2Fwww.pravdareport.com%2Fexport.xml

Which, in summary, presents the following message: "This feed is valid, but interoperability with the widest range of feed readers could be improved by implementing the following recommendations."

I've also checked the feed using Simplepie, which returns said articles:
http://simplepie.org/demo/?feed=http%3A%2F%2Fwww.pravdareport.com%2Fexport.xml

Other feeds on my system are working well.