From that, I'd say that your router needs it's firmware upgrading, or a hard reset.
You requests for the micra page are getting out, and the page is being returned to you, yet your router is turning them down, presumably because it thinks that the IP 84.9.90.214 isn't it's own (when it is most likely the external IP of the ADSL/cable modem). But it also looks like it is forgetting the session as well, which would suggest it is broken.
I can see no reason why this would happen with only one site either.
What make/model is the router?