How can we sort a custom field with DATE using pagination?

Starting at page=1 then moving to page=2 with a limit of 10 each, its all messed up and even shows some of the same records as page 1?

https://www.zohoapis.com/crm/v2/INVOICE_MODULE/search?criteria=(FM_Contact_ID:equals:1234)&sort_by=Invoice_Date&sort_order=desc&per_page=10&page=' . $page

 Now when I use a limit to pull all records (ie. limit=100), it correctly sorts them by the Date Field I want to use.