Haven't read the whole thread but it says on top:
"Edit: This bug seems to occur only when using static IP with Wi-Fi."
My device is on dymanic and received IP from router.
anyway, as said the battery life increases when I just set the connection to connect manually, not automatic.
Also my device is updated with all latest software.

As said now I'm happy with battery life so all good, just wanted to post something that might be usefull to others.

But thanks for thinking.