Impossible to move items from inventory to quick bar

This problem occure with both android and ios version and only with the "horse mythology mash up".
I have to realms. one with horse mythology and another with the default world.
With default world, every thing work
with "horse mythology mash up", it's impossible to move items from inventory to quick access bar. So it's actually very difficult to play because the only way to change items from inventory to quick access is to put / take something to a chest.