We recently started using SVN Keywords to automatically append the current revision number to all our <script src="..."> includes (so it looks like this: <script language="javascript" src="some/javascript.js?v=$Revision: 1234 $"> </script>). This way each time we push a new copy of the code to production, user caches won't cause users to still be using old script revisions.
It works great, except for IE6. For some reason, IE6 sporadically acts as though some of those files didn't exist. We may get weird error statements like "Unterminated String Literal on line 1234," but if you try to attach a debugger process to it, it won't halt on this line (if you say "Yes" to the debugger prompt, nothing happens, and page execution continues). A log entry for it shows up in IIS logs, indicating the user is definitely receiving the file (status code 200, with the appropriate amount of bytes transferred).
It also only seems to happen when the pages are served over https, not over standard http. To further compound things, it doesn't necessarily happen all the time; you might refresh a page 5 times and everything works, then you might refresh it 20 more times and it fails every time. For most users it seems to always work or else to always fail. It is even unpredictable when you have multiple users in a corporate environment whose security and cache settings are forcibly identical.
Any thoughts or suggestions would be greatly appreciated, this has been driving me crazy for weeks.