When the browser is at a large scale, the navigation is a set of full-name links (Artwork, Photos, Etc.), and when shrunk down, it converts to just icons for those links. Unfortunately it looks like the dimensions that trigger that shift is a little off. Somewhere in-between it breaks in two different ways before shifting one way or the other:
1) From around 1342px wide down to 1317px, the notification button overlaps the Support link.
2) At what seems to be exactly 1314px wide, the notification button and user dropdown both shift down beneath everything to a second line.
Shifting to 1313px wide the navigation suddenly snaps to the icons and the other buttons pop back up into the normal alignment. And anything above the ~1342px wide seems to be fine as far as no overlap.
Customer support service by UserEcho