Battery today went down A LOT more than usual and I've actually been using it less than usual. By the way, I did the manual update yesterday in the evening/night.

Looking at Battery Use, my number 1 is "Android Core Apps" - 22% and my number is Display - 18%.
My display has always been number 1, no matter how many apps I'm running... until now.

Android Core Apps - Included packages
com.android.providers.userdictionary
Contacts Storage
Quick Search Box
Android keyboard
com.android.providers.application
Contacts
Home

Is there anything that I can do to fix this?

Droid Core Apps

Same issue. Started this evening after an update.

I had the same problem. I think I've traced it back to the YouTube app. I've started rebooting the phone after any use of YouTube and battery usage seems back to normal.

how can i track the specific app responsible??

I have same problem.
Reboot phone and it back to normal.