Add-on iframes do not load on Internet Explorer 11

Summary

Atlassian Connect add-ons do not work in Internet Explorer 11 since the last release.

Environment

Tested on JIRA v1000.217.1 - Not working
Tested on JIRA v1000.203.1 - Working

Steps to Reproduce

We can try to use any Atlassian Connect add-ons to test this issue, although I'll point out 2 specific cases:
1) Teamcity add-on:

• Install Teamcity add-on on your Cloud instance
• Go to the project administration of a project, On the board click on the Teamcity option:
  

2) Who's Looking:

• Install the Who's Looking add-on
• Open a ticket and observe Who's looking field on the right side panel

Expected Results

Gadgets must work as designed

• Who's looking must show the users looking the issue at the moment
• Teamcity add-on option must be displayed

Actual Results

Who's looking add-on does not load
Teamcity add-on does not load

Workaround

Use other browsers updated like Chrome or Firefox