Unexpected behavior by adding double question mark in the note message body when sharing an issue

When sharing an issue by adding double question mark "??" in the note message body (share screen.png), the share action seems to be failed without any particular reason. But in real, there is a notification fired to the user account with the mail body like "jQuery15202291123343165964_1351507507202" (mail body.png).

Workaround solution: this is a bug had been fixed in JIRA 5.1.x.