When I log in to RB7, the first thing I’ll notice is the unread count badge in the folder list. Then I look over and see the Date and Size columns in bold, but the From and Subject columns will be blank.
Sometimes it will eventually update on its own, filling in the missing details, but other times, I must click to a different folder and back.
I am using the latest version of Firefox. Index synchronization is enabled.
I haven’t been fortunate enough to see a new message come in to be able to say whether behavior is different for new messages that arrive after login.