It happens to me also. I use a Macbook Pro and logged in with all three of the following and have the same issue with all. New posts show the avatar photo and date; have to scroll back up to see the username.
Firefox 48.0.2
Google Chrome 49.0.2623.112 (64-bit)
Safari 5.1.10 (6534.59.10)
Firefox and Chrome are the two I use all the time. I haven't used Safari in a long while ... don't even know why it's still on my laptop.