There is one video on this page that is causing a problem in Firefox only. In FF only (v 20.0.1) the masonry is all thrown off on page load, but fixes itself as soon as I resize the browser. In all other browsers, the video fits properly right from the first page load.
I believe the offending video is the first one (green leaves). When I take it out, everything works including the other video on the page.
Everything seems to be loading properly, no errors thrown with the exception of “Error: Permission denied to access property ‘toString'”. I’ve looked into that one and I don’t think it’s the cause of this issue.