Sporadic 404 File Not Found?

I notice on occasion CS-Cart spits out a 404 not found and then I do a refresh, and wa-la, the product appears. I just noticed it today clicking on the preview link from the Admin Product Detail page. I thought strange, I was just editing this product and this is the preview link so why is it 404 Not Found? Then hit F5 refresh (which makes no changes to the URL), and boom, there it was.