The translation removed can't be added after saving the web content

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 6.1.X EE, 6.2.0 CE GA1, 7.0.0 M3
• Fix Version/s: 6.2.X EE, 7.0.0 M1
• Component/s: Web Content > Web Content Administration
• Labels:
  • QA-R
  • liferay-fixpack-portal-133-6210
• Environment: Tomcat 7.0.42 + MySQL 5.5.29. Portal 6.1.x EE GIT ID: 98bb59ad48c2e527098fae0e1653d08c7349fe81.; Tomcat 7.0.42 + MySQL 5.5.29. Portal master GIT ID: 535110e98665c3f097ce5445daf3ef6c97a022c6.
• Branch Version/s:
  6.2.x
• Backported to Branch:
  Committed
• Story Points: 5
• Fix Priority: 3
• Git Pull Request: https://github.com/brianchandotcom/liferay-portal/pull/15562
• Bug Type: Regression Bug

Steps to reproduce:

1. Go to Admin > Site Administration > Content.
2. Add a web content and add a translation to it.( I choose Chinese )
3. Save the article ( or as a draft).
4. Remove the Avalable translation and try to add the transtion that is removed.

Actual result:
The translation doesn't exist in the add translation list.

Expected result:
The translation exist in the add translation list.