Did the tech that installed the gasket replace the head bolts too? The bolts are designed to "stretch" when properly torqued, and are one-time use only parts.

Reusing the head bolts is a definite no-no, and since the old ones won't stretch with torque settings upon replacement, they can and probably will work themselves loose and breach the head.

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car