Tagging a family photo with all members without uploading it to each of their memories.

I found a photo with both parents and eight children. Once I tagged the father, why can't I simply start typing in the tag boxes to add the mother, then all the children via the father's memories screen? I used to be able to do that. Now I have to individually upload the same photo from the gallery to each person and it takes forever even keeping several tabs open. It used to auto-fill if there was an existing record for that person. I also tried using the number to make it connect and that doesn't work either.