Ask HN: Are you seeing lots of broken images in Gmail?

Ever since they announced caching of all images, I am starting to notice that almost every email I receive in my Gmail account has broken images.

Getting out of the email and back in seems to be solve the problem most of the time.

I fired up Firebug and noticed that Google's proxy server is returning a 404 on the images the first time the email is loaded but, after a few more calls to the same URL, the image is returned.

Does anyone know the cause? And if there is a fix? We send out a monthly newsletter and getting lots of reports from our users about not being able to see images.