I don't know where you got that idea, but I don't think that happens at all .... The only reasons that they send applications to another office, I.E. the home country or something of that nature, is because there are concerns with the applicant or the relationship itself. They need more time to dig and find the answers to satisfy themselves. Once sent to the 'local' office, it takes you out the of regular 'stream' so they don't have to hurry to complete it. More often than not, the applicant will be called for an interview if the file is transferred.
The ONLY office I've heard of shuffling applications for overload, is New Delhi to London.