In the structure minecraft:village/taiga/houses/taiga_armorer_2, grass blocks generate beneath the stairs that surround the blast furnace. These grass blocks get converted to dirt through random ticks, so there is no need for there to be grass blocks at all in these places.

In the attached screenshot, orange represents path blocks (intentional), lime represents grass blocks (intentional), green represents grass blocks (likely unintentional), gray represents cobblestone (intentional), and brown represents dirt (intentional).