I seem to be encountering a strange FB behavior on both my Lumias - 610 and 800.
I don't know if it existed from the beginning, or it has just been noticed now.. but the strange fact is:
While my "Me" Hub gives me an update on notifications, it actually does not show the comment in the case when the status was mine. Allow me to explain it:
If I update my FB status thought "Me" hub, and one of my friends comments on that status, I do get the notification in the notification area of the hub, and clicking the notification even takes me to the status message, but the comment left by my friend is not visible.
This is true only for the status posted by me.
For the status posted by others, I do get the list of all the comments / responses their status has received.
I sort of have the same problem. In my people hub if I see someone commenting onto someone else's wall, it might have 5 comments, but when I click it no comments show up. I can only see comments when it's just someone making a status on their own profile.
But I don't believe it's entirely the People hub's fault because even the official FB app can't show the comments and I then have to go to m.facebook.com to see it.