According to the blockstates files, structure voids use a model named structure_void.json and even randomly rotates it.
This model states that it uses cube_all as parent and the textures being items/structure_void.png.
However, this model doesn't load, even when edited.
MC-102210 it's intended that you can't see structure voids after placing them.
It should then just have a empty model or have no model nor blockstate files rather then completely ignoring the model(s) as that only provides inconsistency.
I provided the files of the 1.10.2 jar in the attachments.