Leaving an update. I did a bit of experimentation where I removed the sensor, factory reset it, then re-added and re-configured it, then started with a detection interval of 30 seconds and increased it by 10 seconds at a time until it would no longer Detect & Clear successfully.
60 and 70 seconds sometimes work. 80 seconds causes the sensor not to clear at all until I turn the interval back down to 30; going back down to 70 didn’t. I didn’t bother to get more precise. This is surprising, considering the advertised maximum interval of 200 seconds.
I’ve decided to keep the sensor’s detection interval at 30 seconds where it’s happy, and set 180 seconds in the ocupancy_timeout field. That’s giving me the results I want.