Can be multiple modes of Failure
Not flat anymore and beyond sealing capability of head gasket.
Crappy graphite steel cored gaskets, they only have @ a 2 year lifespan.
Chassis flex causing head to be shifted around
Studs need to be replaced stretched slightly and becoming elongated
Detonation causing head to lift
Over heating
Over torqued and pulling threads out of cylinder
or combination of multiple from above