occasional broken page (post in the left edge)

[crazycells]

from time to time, when I open a topic in a wide full screen, I see something like this:

The first post on the top of the page can be seen doubled and one of them is squeezed into the left edge of the page. How can I find the reason for this break, and how can I fix this when this happens again?

It only occasionally happens (once a week or so); and usually, when I refresh the page, it goes back to normal. But this break is reported by other members of our forum as well.