Most of the time i sync manually and it works just fine however sometimes i get the 'invalid feed' message and that feed doesn't update, i solve that by trying again a couple of times.. But like i said most of the time it works fine just very slow which is my main problem with the n9.. People talk bad about the lumia on this forum but i have one and it does things literally three times as fast as the n9, every little thing from syncing feeds to even going from one settings menu to another.. Anyway sorry for being off topic..

im not sure how to fix the issue where the feeds wont sync even manually.. Maybe try reflashing, i did that and solved many issues while keeping all the data!