Random images not created in views list of images

I have views displaying a list of 200-400 images per page that are processed with imagecache.

When the page displays 3 or 4 random images at the beginning of the page do not get created by imagecache but the remaining do. If I reload the page then the missing images get built fine.

Is there some things to check to see why these images are not being created on first page load? I checked in the imagecache file directory and they are no there until I reload.