In looking into a problem where CCK field data was being 'lost' when first submitted (it wasn't entirely lost, but missed out on being stored in the cache), the Remove Non-viewable Menu Items module turned out to be causing the problem.

More info:-
http://drupal.org/node/158237#comment-988768

I think it is caused by the call to node_load on line 60.

Have you got any ideas about how to solve this problem? I have tried changing the weight of the module, without any success.
This is a very useful module, and it would be great to find a fix for this issue.

Let me know if you need any other information.