I'll create a support ticket to attach my data so you can see this.

What happens is that when I click on the printable view of an issue it shows me a comment from another issue. And when clicking on a link in the printable view (of a JIRA issue), I get an error:

Error 503--Service Unavailable
From RFC 2068 Hypertext Transfer Protocol – HTTP/1.1:
10.5.4 503 Service Unavailable

The server is currently unable to handle the request due to a temporary overloading or maintenance of the server. The implication is that this is a temporary condition which will be alleviated after some delay. If known, the length of the delay may be indicated in a Retry-After header. If no Retry-After is given, the client SHOULD handle the response as it would for a 500 response.

Note: The existence of the 503 status code does not imply that a server must use it when becoming overloaded. Some servers may wish to simply refuse the connection.