head gasket problem

[sassanach0]

i removed today the head gasket of a 2.0 ecotec engine that i had replaced 6 months ago.the fire ring on no 1 cylinder was split horizontally at the fold, is this just a manufacturing defect or is there a underlying cause? the car is factory fitted with lpg

[Kitchski]

Do those engines use liners, or are they iron blocks? If it does use liners, could be that ones dropped?