I have a fluid width theme and I am using jQuery Masonry and Infinite Scroll. The Problem is that if you scroll at a certain speed (not too fast and not too slow) the page it can cause a break in the grid. I have only seen this with two columns and in Firefox:

Anyone know why this is happening? I know it could be a number of things but if anyone has had experience with this and knows what is going on it would help greatly.
UPDATE:
The break happens right after the last post on the page. The ones that come after are being generated by infinite scroll’s callback.
Well, I can not see the link to your page to look at (and the image is not available) but from my past experiences with masonry, whenever there is a major change in the page size (re-sizing, scrolling, re-sized divs) you need to trigger it again: