Quote Originally Posted by jick.cejoco View Post
there is a possibility the cylinder head bolts were not torqued to the right value or the cylinder head bolts were installed and torqued in the wrong sequence. as a practice in the past, the cylinder head and the cylinder block mating surfaces were sanded down in attempt to clean it. this removes the certain degree of roughness on the surface to prevent the cylinder head gasket from sliding too much during heat/cold cycles of the engine. if the clamping force of the bolts is not enough or the surface condition being too smooth and slippery, then the gasket keeps sliding and create a gap allowing pressurized gases and fluids to go past the gasket seal
to the TS, this might help a lot too...maybe the headbolts were not really torqued to the right specs and sequence. could be that your mechanic just did the "usual tightening". mine bubbled also about a year after the gasket job. retorqued it again to specs and right sequence, bubbling issue gone.