So since is a major indicator for longevity of our MBP...how are your temperatures under stress for dGPU?
Say your dGPU model and max tmp
For me 450 here it didnt reach 80C it stood around 70-74C
The classic failure mechanism of the MBP`s dGPU is related to thermal shock, as Apple in general opts to run consumer grade components as close to their upper limit as possible. This in general takes several years to rise it`s head resulting in premature failure of the dGPU. As for the longevity of the 2016`s dGPU we will see in time. The only real early indicator is operating temperatures; if Apple`s 2016 design can keep the dGPU below 80C - 85C under load it will be a good indication that Apple is looking to improve reliability.
This case is more likely to related to a production error, one of the risks of being an early adopter; new hardware, new processes, new assembly technicians etc. one of the risks of being an early adopter with Apple.