I have the 'M8952_70030.25.03.62R' baseband.
I have tried without any third party apps installed, facing the same issue.
If in case it was a baseband issue, I would be interested in flashing the latest baseband.
Would you be kind enough to point me the right direction?
You do have latest baseband version.
This issue happens when phone gets heats up and battery stops responding (power cut) to lower the heat radiated.
If im right according to your telling ill suggest you to take the phone to service centre. It is more a hardware problem then the roms itself.
How do i know?
Simple, experience.
My friends g4 plus suffers from same issue(not on calls but heat issue) and service centre guy told us this reason.
Well i may be wrong as information is incomplete.
Fill in this :
Battery temperature.
Background activities.
Mostly with calls and other than that (if happened).
You told all/most roms, may you name some with build date and what/how issue existed in all of then.
Also battery supply voltage(use my device app).
Try the same issue like this :
Plug in your phone charge it and play heavy games.
If device reboots you got your solution, if not then recreate the scenario and tell us exactly what happened.