Migrate from another CRM - Owner Mapping does not work?

Migrate from another CRM - Owner Mapping does not work?

I've been emailing Zoho support for a week on this and they keep giving me a superficial answer which is that this function SHOULD work, but it DOESN'T. Which they haven't tested or tried to tell me what's wrong. I'm at a loss at how not helpful they've been.
 
Hopefully the Zoho Community has a solution?
 
When I upload from Migrate from Another CRM and map the Owner Field (using owner email address) everthing still imports under my name? How can I get it  to work to assign to the actual Owner?