I also think that the problem is often caused by the hardware. I have noticed that inside the app Kernel Adiutor (Statistics/Vendor) my Qualcomm processor hardware is shown as MSM8974PRO-AB and if I look at the processor info of my friend’s FP2 which has problems with random reboots it is shown as MSM8974PRO-AA. By the way processor info can also be watched in Settings/About phone/Processor info.
Problems on the FP2 of my friend could be minimized by reducing CPU maximum frequency, Sync Threshold and Input Boost Frequency by one level, i.e. 1958, 1574 and 1267MHz. Additionally I observed that one core was always off (possibly misadjusted by factory?) and I activated it manually using the slider in Kernel/CPU.
But maybe this is a singular case.
Does anyone have random reboots with the “AB” processor and none of the available workarounds are useful?