The Javascript files are getting corrupted with "illegal characters" appended to them OR characters truncated off the end. At first this was happening almost randomly, but now I think it is related to file changes. For instance if I edit the files, then I get the corruption immediately. This occurs if I edit in my IDE (Zend Studio) or by ssh'ing in and editing with vim or simply using TextEdit. "touch"ing the file doesn't cause the problem. But any changes to the file does cause the problem. The corruption (garbage characters/missing characters) is only visible if I open the Javascript "file" from my browser (Firefox using Firebug console) and not in the editors themselves (although sometimes I have seen a new blank line at the end of the file).
I thought it was a browser caching issue, so I disabled cache in my browser without any luck. I have also tried other browsers and had the same issue.
I have also tried every possible combination of permissions on the shared folder.
The only solution I have found is "shutdown -r now"

How are the files getting corrupted? Can anyone help me?