Auto-sync is turning itself on randomly (Nexus 6 on rooted stock Android 7.1.1)

I have a feeling a rogue app is turning on auto-sync, but is there any way to discover which one? 

I checked that it was switched it off this morning and at some point in the last 4 hours, it has come back on without me doing anything.
The rogue app that was switching on auto-sync was Kana Town 
https://play.google.com/store/apps/details?id=fr.koridev.kanatown