My temps and hardware are fine, i have no issues at anytime with any other games, all stress tests are fine, its just this game when ran via the launcher.Sounds like you have a system issue, maybe a over-heating GPU ? Do you monitor your temps ? I use to have similar issues with my old computer, on cool nights it was fine but in the day, hot days , it would play up.
I use a program called hWinFO64 , it shows many conditions in the task bar - CPU temp, Motherboard temp , ChipSet, GPU, Fan speeds etc etc. You can also set Alarms .
Don't forget to test your hardware.