it's supposed to be dry.... where is the water coming in from? Wear something gray as your outermost layer and after the first dive, see where you are wet.
Assuming the seals are in good shape and the zipper isn't leaking, here's where I'd start looking.
Make sure the neoprene neck seal is actually sealing. Neoprene neck seals take a bit of practice to get them rolled properly and if you are contorting yourself or have hair in the way, it can leak quite easily. They're really comfy, but not as good of a seal as latex.
Turn the dump valve back a couple of clicks, some of them will leak a bit when they are open all the way.
These suits are prone to pinhole leaks and with the merino lining they are damn near impossible to trace. If it was pressure tested "inside-in", then it's possible that the pinholes didn't show because the suit normally leaks when it is under vacuum. Try the gray clothes trick and see if you can nail it down where the water is coming in.