If I have a full stack of an item in an invisible bag it doesn’t move when I use the compact option.
However, If I have a part stack in the top bag and the full stack a quantity equal to a stack minus the amount in the top bag will move up from the invisible bag and into the top bag when I compact. With a stack of 50 in the top bag 200 will move up and form a new stack leaving 50 in the invisible bag. I then have to move it back.
This should be an easy to fix item but something makes me doubt that.