ListBox "sort" field which describes default sort is implemented using ListTextAreaField. As you can see it replaces single value "V" with "V | V". This works for sort/search columns definition because they expect "column-name | title".
ERP5 (SelectionTool) is benevolent and gracefully omits such meaningless sort expression as "id | id" and sorts ASC by default.
Old UI is very nice to the implementator and shows sort as ascending in case it is not descending. Which is true but leaves the implementator to get lazy with definitions.
New UI refuses to show any sort which is not properly defined. Thus sort values in ERP5 has to be defined as "<column> | <order>". Examples: "id | ASC", "title | DESC".
Test Result https://nexedijs.erp5.net/#/test_result_module/20170727-1803130F