if all are glazed I would suspect the machine work done by the shop. Need to check piston to cylinder wall gap. What they claim and what is actually there could reflect the problem. What pistons are you running? Forged pistons need a slightly bigger gap for the expansion rate of the silicon in the piston. Different piston composition and boost levels need to be dialed in properly for piston to cylinder wall gap. Most regular machine shops don't get it right for the VG block.