Global users invited on subwiki can`t use Invitation app

1. Create a subwiki (on a clean instance of XE 7.4.2 ) with settings:

• User Scope: Open for any user to join
• Membership Type: Both global and local users are available in the wiki
  2. Create a global user on the Main wiki.
  3. Login on the subwiki with the global user and click on :"Join this wiki" to become a member.
  4. Login with Admin on the subwiki and set the same rights for the global XWikiAll group as the local XWikiAll group.
  5. Login with the global user on the subwiki and click Invitation panel icon.

Actual result:

• Global user, that is now a member of the subwiki, with the same rights as a local user will get this error message: "Sorry, only members of this wiki can send mail. You seem to be a member of xwiki which is a different wiki."
• If you register on the subwiki, you become a local user of that subwiki and you are able to access and send invitations.

Expected result:

• I expect as a global user - member of the subwiki - having the same rights as a local user - to be able to use Invitation app.