Xiaomi Mi5 facing sleep of death issue. Please help!

My Mi5 is facing a weird issue.
Have jotted down all details below.
Has anyone else faced this issue?
What is the fix? Please help!

1. The phone works fine as long as the screen is on. It does not hang or face any issues.

2. After locking the phone, the screen does not come on (this happens sometimes not always). It always happens when I leave the phone un-touched for a while. The phone remains on (I can hear the lock sounds, phone ringing and also see the keypad lights) however the screen does not come on. I need to wait for a long time for it to work after multiple presses of the unlock button or I need to restart the phone.

3. I do not think it is a screen issue because it works when on. I think it is the 'sleep of death' issue.

4. I have reset the phone. I have re-loaded the global MiUI 8 ROM and also tried loading the developer rom. I have not rooted the phone so far. Happy to do it if needed.

5. The issue does not happen if I have the music player on and lock the screen. It tends to happen only when the phone goes totally to sleep with no applications using it in the background.

Please let me know what I can do to fix the issue. Thanks.

 

Thanks.

Tried that.

I did a factory reset but the issue is the same. Was on the stable MIUI 8 ROM.

Tried loading the Developer MIUI8 ROM as well. Same issue.