Nexus 5X stays awake after charging Nexus 5X running 6.0.1 shows awake after disconnecting charger cable.

Reboot helps but later the awake state persists if I connect charger back.
I've found the root cause for awake state - it is Viber.
To detect this I've completely removed all third party software and left only one came from Google (my Nexus 5X comes only with Google and no bloatware).

So adding apps one by one I was checking the issue appearance after every.
The issue back after adding Viber and immediately has gone after removing it.