Data are not rendered correctly

Look at the screen above . Activity data are not presented correctly. It happens when I set Autorefresh ( doesn't metter how often) and wait an hour or two. And it is enough to move a little an activity window above and all goes back to correct render like in screen below.

Do you experience similar problems ? Any Idea how to repair it/ correct it? Could it be my browsers fault? I mostly use Firefox

regards,

K.