Attachment preview and download in Jira's issue view is not working for PDFs, XLS and other DOCs

Issue Summary

When trying to open attachments, it's not possible to preview or download attachments from the issue view in Jira. The issue occurs in both Jira Service Management and Jira Software projects.

Steps to Reproduce

1. Try to preview/open an attachment from a Jira issue
2. Opening the attachment will produce a blank screen

Expected Results

Attachment preview works properly

Actual Results

A blank screen appears and users must refresh the page to get back to the issue view.

Workaround

If you're trying to open from a JSM issue, use the Portal view instead.