The recent updates have caused problems for a lot of people. I haven't experienced any myself, though.
I was also on the beta until this morning. I went to
http://android.com/beta and un-enrolled from the beta. Then, I downloaded the latest OTA image for the Nexus 6P (build N4F26J). Before I could apply the update, my phone received another update (N4F26I) which is also January, 2017. I was afraid it might force me to wipe my data, but after installing the update and rebooting, there was no forced wipe.
I don't know what the differences are between the two builds (N4F26I and N4F26J), but I figured I wanted to be on the latest build so I went ahead and sideloaded it via ADB.
To recap what I did:
-Un-enroll from beta
-Install new update
-Reboot
-Download N4F26J
-Use ADB to sideload N4F26J
I'll see how the battery is over the next few days. I didn't have any issues before, though, so there *should* be nothing to fix.