I don't think I live in a dry climate.
Yes, I leave water on top of the soap for a minute or two before using it. Isn't that called "bloom?"
In my experience of having gone through a dozen MWF pucks, it's the blooming that causes the cracks once the water evaporates.
I take a slightly damp brush to the soap and once loaded, wipe off excess lather from the puck. Haven't had a single crack appear since I stopped wetting the puck before use.