Little air pockets

after pulling a boat out of the mould I experienced little air bubbles popping out of the gelcoat in patches only in the hull.
Hand layup with one layer of CSM one layer of 450 carbon double bias ( customers request I usually just use glass DB ) and a carbon cloth on top
It's a new model and a few scenarios are running through my head
It's the carbon double bias not wet enough in patches
I may have put too much gel on
I did use a small amount of older gel coat ( spraying ) in each pot of gelcoat( 3)
I changed the air pressure slightly up
2 be boat out of the mould with the first one being good

Any ideas anyone ?