I can't think of any specific reason this may be happening based on the video, but that may be because the menus you opened for some reason were not recorded.
Since it isn't shown in the video, I'd like to ask you if your duplicate special options are the same as in the picture attached. I tested it with these settings and it seemed to work normally (though I am on Maya 2020 instead of Maya 2019, so that may affect something).
