I just got a reply from NSP to an email on the same (original)subject:
"NSP boards have moulds for each size in their range.
Meaning they blow blanks to fit each size mould.
Meaning the blank is blown to fit that size minimising the gases.
Generally cheaper SUP's or smaller volume brands tent to blow one size fit all blank and cut down to size for each model.
This usually leaves the blank with a lot more gases.
That's why they insert the vent plug.
Having a vent is fine and the quality is still good it's just that NSP don't need them.
I only know of 3 delams in the last 3 years through NSP.
They are considered the industry standard. I'm sure your replacement will be fine"
So I guess all is good, I must have had a board made on a Friday arvo