Try clearing your cache. The path is changed for this static file to improve cacheability. javascript.php ensures that various headers are set to try and ensure that the browser caches the file, and is designed such that subsequent calls for the same file where the browser provides a Last-Modified header just result in a 304 not changed. javascript.php also minifies the files on the fly. The timestamp is to ensure that when you upgrade Moodle, the timestamp is reset, thus changing the URL, and a browser will re-request a different file.
If you clear your cache, this will remove the existing server cache of the minified file, reset the timestamp in the URL, and this should mean that you get the file served. Most likely, something has caused the cache to be incorrect somehow - this may happen if your storage is flaky for example, or something odd happened the first time the file was requested and a dodgy copy was stored. This shouldn't happen, so if know the cause, it may be worth raising an issue so that we can prevent similar things happening again.
Andrew
