vTiger 7 - Events - Label text incorrect

When viewing with a User whose language preference is US English - Creating an Event in Calendar the 'Invite People' text displays correctly. After the Event is saved and viewing in details view, the text changes to 'LBL_INVITE_USERS' - This Label is defined in the en_us\events.php file ('LBL_INVITE_USERS' => 'Invite Users',) but does not display correctly. The text Label used in Edit view is LBL_INVITE_PEOPLE

So the Label text changes from one variable to another, and the second one doesn't display properly.

When viewing with a User whose language preference is British English the same problem occurs and as well LBL_INVITE_PEOPLE' => 'Pozovi Ljudi' which is not English and should be 'Invite People'

Surely should display 'Invite Users' on both edit and detail view