S7 edge died and shows red light

Hi guys,,

I'm having issue with phone customer (S7 edge) that died randomly, so just to give more details about the device, I had to do screen replacement for it and all went smoothly, every things was working fine, the customer picked it and called me the next day reporting that his phone died, he bought back and i did hard reset and updated firmware as there' was update so I though that would fix the problem and then it died,

I tried to get working again but showed error kernel could not boot normal and after I disconnected the battery and did hard restart and I got working but after two hours died and showed solid red light and try to do everything (hard restart and try boot in safe mode but things helped, forgot to mention that I have reinstalled the firmware through smart switch but same thing happened died and show red solid light.

I'm still assuming it's software issue as the phone could boot up normally after disconnect and re-disconnect the battery,

I did run hardware diagnose tools but all are fine!!, sensorhub self test says INT check ok and test pass !!

I'm wondering If the there any application to diagnose this problem?

Its really making me crazy,

Any solution would be really helpful.

Thank in advance.