100+ 9.7 iPads,20+ iPad Pros, and about a bakers dozen of iPad Minis less less than 6 months old all have reported a 33 to 50% shorter battery life. Fucking wonderful iPadOS, same old apple bull shit.
Previously it was just Spotlight, but when Photos added Faces and object recognition, kept locally on every device and not sharing among them, the length of time it spends re-learning ballooned.