Antipodes
Queen Bee
Glad you have found the root cause, but what a weird thing for a manufacturer to do. I wonder how poly langs compare to that?
So all wooden langstroth boxes commercially made in New Zealand and Australia have a top AND a bottom bee space. It's not just in the Southern Hemisphere but in the USA.
Over there, Mann Lake and Dadant wooden boxes in a deep langstroth are 9 and 5/8 inch deep and the frames are 9 and 1/8 inch or about 244.5 and 231.8mms. so about 13mm difference. You can see the measurements on their websites. Presumably that gives them either a whopping top space, much bigger than a bee space, or like here, it is shared top and bottom making an extra big space between all the boxes. That causes issues when the bees join the frames and put honey and drone brood in them (as per the Amazing Bees article I linked earlier).