Comments not working across portal/sites if MB staging is enabled on one site

• Type: Regression Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 7.0.1 CE GA2
• Fix Version/s: 7.0.1 CE GA2
• Component/s: Collaboration, Comments, Staging
• Labels:
  • KNOWNISSUES_DE70
• Fix Priority: 4
• Sprint: Ferroskutterudite
• Git Pull Request: https://github.com/brianchandotcom/liferay-portal/pull/40498

Reproduced on:
Safari 9 + Tomcat 8.0.32 + MySQL 5.6.29. Portal master GIT ID: 47ef4247949e5bada12bc68d2b065bd9051708aa.
Firefox 38 + Tomcat 8.0.32 + MySQL 5.6.29. Portal master GIT ID: 47ef4247949e5bada12bc68d2b065bd9051708aa.

Steps to Reproduce #1:

1. Go to Liferay > Publishing > Staging
2. Enable Local Live staging with Message Board assets selected
3. Go to staged Welcome page
4. Add Page Comments portlet
5. Input comment
6. Click Reply
7. Create second site
8. Add page to new site
9. Add Page Comments portlet
10. Input comment
11. Click Reply

Steps to Reproduce #2:

1. Go to Liferay > Publishing > Staging
2. Enable Local Live staging with Message Board assets selected
3. Create second site
4. Go to New Site > Content > Documents and Media
5. Add new Basic Document
6. Click to view added document
7. Input comment field
8. Click Reply

Expected Result:
Comments can be added and display to the user.

Actual Result:
Comment not created and does not display.
Javascript console throws ReferenceError: Can't find variable:

Also reproduced on Calendar Events, and in My Workflow Tasks.