This is the result I get after applying several changes I got from the web, to fix the no-deep-sleep issue.
Basically, this was what I did was:
1. Reset network settings (Settings - Connection & sharing - Reset WLAN, mobile... - Reset settings)
2. Cleared Google Play Services data and updates (Settings - Apps - Manage apps - Google Play services - Uninstall updates & Clear data)
After a reboot, I charged my phone to full last night.
At around 4 am, Whatsapp woke the phone and kept it awake, so I put battery saver for Whatsapp to "Restrict background apps". The phone went back to deep sleep.
Might or might not work for you but it is worth a try.
View attachment 30912 View attachment 30913