New version 96~97 doesn't let you copy more than one items.
Happens both when you copy grouped items, or select multiples.
It ends up copying 1 random thing from the group/selection.
Only exception I found so far is tatami loft, so maybe it's working for new items and not older items/groups? Bottom of tatami loft dyes too in game by the way.
On a positive note, new version looks absolutely amazing! Fantastic job on lighting, looks so much better.