there is a difference between 'start production' and 'start filming'. There are months of pre-production work before a movie starts filming. Railroad Tigers is in pre-production now. Filming is due to start in October. Kungfu Yoga - is in casting ie it is not even in pre-production yet.
For feature films, pre-production only begins when other milestones have been met such as financing, screenplay, casting and major staffing.
So for Kungfu Yoga - we can tick financing, script and director, the only person who has been cast is Jackie. They are apparently searching for co-stars at the moment hence all the news about this and that person being approached. So there is still a lot that needs to be done.