Tablet maket columnsColumn settings not working in tablet mode

how to repeat:

1. Create two columns 6+6
2. Fill with any content
3. Customize 12 columns display in tablet mode and mobile phone mode

Result:

1. In tablet mode (vertical and horizontal), the columns are the same as when creating a row
2. In landscape phone mode - the columns are the same as when creating a line with columns

In fact, this functionality does not work at all?