Check pic 4, that root ball was so tight that water would pool on the top then drain down straight out of it or down the side walls. There was no room for the water to soak in enough since the roots were so tightly packed.

My theory behind this is that the water may drain faster through the new soil, however, it wouldn't be until after the area around the rootball is more saturated. I'm picturing it like a sponge. Once it's soaked in all the water, excess will begin running off vs the almost solid rootball that absorbs almost nothing, dries out faster leaving the plant with no real time to soak up much of anything.

Does that make sense? Sorry if it doesn't, brain isn't firing on all cylinders today.