Regarding those Nissan head gaskets; those were all under warranty as leaks were occurring within 5-10k miles. Warranty required gasket replacement and which was the proper method.
As to tightening the head bolts to stop the oil leak that’s just my personal opinion that was never put into practice. Subaru put out a bulletin about retorquing head bolts to stop oil seepage issues and it worked for them although granted the oil leaks on Subarus was no oil under pressure.
The oil port was located a 1/4" away from the edge of the block and the slightest looseness due to HG relaxing would cause oil under pressure to weep at a minimum or drip steadily at worst; all because the head bolt check was eliminated. There was never, ever a defect found with the blocks, heads, or gaskets. It was simply due to the above reason.
As to retightening of head bolts, SAAB also had a notice about this.
There’s even a cut and paste statement from Fel-Pro about this issue.
“Some competitive head gaskets alleged to be “no retorque” can lose as much as 50 to 60% of their original torque after only 100 hours of service.”