Insecure Content Warning in IE8 over HTTPS when editing labels on issues with comments

When editing an issue's label (editing meaning creating/removing a label and saving the changes) on issues with at least one comment, IE8 will throw a Mix Content Warning. Deleting all comments and editing the label again does not throw the warning.

Tested on JIRA 5.2.5 and 5.2.11 fresh install.

Screenshot: InsecureContent2.jpg as we can see from screenshot this is a fresh instance with zero customisations, on a new issue with only 1 comment. Editing the label throws the warning.

STEPS TO REPRODUCE:

1. Install a fresh JIRA 5.2.11/5.2.5 instance.
2. Create a new project, and create a new issue.
3. Add a comment to the new issue.
4. Edit the labels, add a new label, and save the edit. Observe that the Insecure Content Warning pops up like a boss.

IE8 version tested: 8.0.7601.17514
Note that this does not happen in other browsers, or IE9 for that matter.