Does anyone know of redirect problems when they're editing a post in 3.5.4?

At the moment I can edit my own posts and redirect back to them, but anyone else's and it shows a blank screen (although it does actually edit the post).

Anyone know of a similar problem they had? I've checked the files relating to edit post and showthread etc, with all the functions_*.php

So far they all work and all are the original files sent with the package.

they're all 775 chmodded as well. Is there a registry or something I should check?