Hi there, I also updated with the 20171219 using local updates by coping the zip to phone, made factory reset but no change in battery drain problem.
Phone has a sim and a microSD card.
Tried the update twice. It seemingly updated successfully.

Should I try something else?

geoc wrote:

Hi there, I also updated with the 20171219 using local updates by coping the zip to phone, made factory reset but no change in battery drain problem.
Phone has a sim and a microSD card.
Tried the update twice. It seemingly updated successfully.

Should I try something else?

You'll have to flash it, as local update is not working correctly.

Refer to this tutorial:
viewtopic.php?f=192&t=319505