SuperTables: Why certain elements do not have an aria parent role?

ARIA Rule : For every column header ARIA parent role must be added. 

By default, SuperTables has column header’s role described as role=”columnheader” - element containing a column header. For all the members cells there is an ARIA-Describe By tag which explains where it belongs.  However, even though all aria tags have been applied to the necessary elements, some screen readers have trouble navigating the tags when the structure of the grid gets more complex (eg. grouped columns). This is the reason why there are some limitations announcing the correct column names. Check the Product Guide for more information.