I just had the same as Chris. I also get problems in receiving my mails after a member has posted a reply. I need to constantly refresh the pages where I had replies to see if there was any other replies added. This happened yesterday and the day before for a while, then all of a sudden I get a ton of mails that was about 3 posts late.
Since yesterday afternoon all was well again, so I'm holding thumbs. I see Davey is using Chrome, which I am as well. As Chris mentioned, I don't think it is a browser specific problem. The problems also seem to come and go.