Also works for me, but only after relogging to the world. Have you tried this?
Also confirmed for 16w21a
Not sure if it is a bug, but a possibility to see the structure void blocks just like the barrier blocks would be a nice feature.
Also not working for save and corner mode. Working for data mode.
Yes, I can confirm that is fixed with 19w03a. I must have forgotten to remove the old copy of the world before testing with the new snapshot.