`Zone enter` and `gps_accuracy`?

I have a near_home passive zone set to 600m around my actual home. Today I had an “enter zone” trigger fire even though I didn’t enter near_home. The following chart was generated with a proximity distance sensor from home running at the same time:

The event fired at 13.21:45, which corresponds to the highest point on this chart (around 719m away). In the trace, I have both the to_state and the zone in the changed variables, and putting those coords into a distance calculator[1] does indeed return 7.2km. The only thing I can see is to_state.attributes.gps_accuracy is 142 which in the pessimistic case would have put me in the zone.

Is gps_accuracy considered when working out if a device_tracker is in a zone?

[1] eg Coordinate Distance Calculator

This has been problematic since I posted so I replaced the zone with a numeric_state trigger and proximity distance (which uses the coords regardless of accuracy). All works okay now.