I have geofencing feature on but the battery usage is quite low. Sesame is 4th from bottom on 7 day usage list (4min on screen 14h background) and didn't even made it to the last 24hrs list. I had both Auto Unlock and knock feature on, but turned off the latter due to more false positive cases.
I have had Sesame burning through my phone battery before, but it hasn't been an issue for the past year or two. (latest iOS, iPhone X, 7, SE, 4s..) That being said, auto unlock works about 70% of time so I wonder my sesame app is not working as hard to look for the door lock.
I would recommend the usual house cleaning. Restart the phone, delete and reinstall sesame app, and so on. Hope it works.