Limit is 500x300 - not 500x260 + 270x260 + 500x260.
Due to the large width at least two will appear above each other if viewed in a resolution smaller than 1920x1080 for Underground and Brave skins or 1680x1050 for the Default one - which means this affects a majority of people.
Well, you should realise that if I point things out to someone I have a good reason. It's very rare that I am wrong in things like this, especially because I make sure beforehand...