sub_row_grid and mygrid.toPDF

I am successfully using sub_row_grid. And I am successfully using mygrid.toPDF. However, when I attempt to do both, that is when I attempt to have my sub grid show up in my pdf, the sub grid rows do not appear in the pdf, only the main grid rows show up. How can I include the sub grid?

Unfortunately it’s not available to export the subgrid.