Images with special characters in the filename don't get rendered on error

I attached an image with the name ~!@#$%^&*()_+{}[]"'.jpg and when I insert I can see it fine.

However when I click save and produce an error (i.e. no title), the image isn't rendered anymore. I suspect that tinymce is the culprit because when you look at the url it is http://mce_host/confluence/download/attachments/8323077/%7E%21@%23%24%25%5E%26*%28%29_%2B%7B%7D%5B%5D%22%27.jpg?version=3&modificationDate=1304986880115. I have no idea where the mce_host comes from.