Pivot table sorting by date bug

Hi,
when sorting programmatically a pivot table using the “date” type, the asc direction will toggle between asc and dec, while the desc direction will stay desc.

Please try to order the following pivot clicking on the “Sort asc” button repeatedly:
https://snippet.webix.com/n2qfzdz9

Can this be fixed? I need to sort programmatically and the behaviour is not predictable in this way.

Thank you