When exporting data in csv/pdf format from ajax sourced datatable, incomplete data is exported.

Link to test case:
Debugger code (debug.datatables.net):
Error messages shown:
Description of problem:

  ajax:{
        url:'https://restcountries.com/v3.1/all',
        dataSrc: ""
   },

When exporting data, incomplete data is exported to file(only 1 random row of data) instead of all data rows in the table. Why is that and how to fix?