Proximity not set, using google maps sensors

I’m sort of pulling out what little remains of my hair with this one. I’d not bothered to update HA for a long time (it works, why mess with it) and finally got around to it this week. Alas, after renaming all my sensors that now have extra _s all over them, I’m left with one that just doesn’t want to play: proximity.

I can’t for the life of me figure out why it isn’t working. It matches the docs exactly, both the Google Maps sensors show on the map, the home zone is where it’s supposed to be, it just doesn’t want to play. Anyone have any ideas?

  - name: home
    latitude: !secret home_latitude
    longitude: !secret home_longitude
    radius: 50
    zone: home
      - device_tracker.google_maps_109984549047371398743 #dan
      - device_tracker.google_maps_112049465177067192481 #eric
    tolerance: 5
    unit_of_measurement: mi

both from my configuration.yaml

No matter what I do (and I’ve been banging on this for hours now) it just returns “not set.” Any ideas?