I've been encountering this problem lately, where blog comments with mentions of myself don't appear in the default feed, the view you see when you click the start icon at the top of the page. I can still find them in the Mentions subsection though. Took me ages to figure out why the star had a 4 next to it but I'd only have 2 new things on the feed.
Pretty sure this is a bug. Anyone else encounter this?