I’m specifically looking for the times when the app/device stops sending updates for a technical reason, so would expect there to be precisely zero changes to the state/attributes[1]. I suspect the speed integration will fall foul of the same issue as proximity (but even if it isn’t, I think I can solve the issue with my existing approach)
The trigger is firing much faster than that, every few seconds. Even if incorrect, I would expect it to only fire once every two minutes:
[1] Determine proximity direction over time rather than with subsequent location updates