OK, I'm starting to get to the bottom of this, well to get a better understanding of these anyway.
Leaving the driver options out of it for the moment, at the fundamental level what I'm observing alights with what you all are reporting.
The long and short is that the device isn't capable of honoring Lux threshold reporting settings in the expected manner.
OK, so what happens if we tell it to report lux every 60 seconds (or hit refresh every 60 seconds)?, it does return a value, however it does not take a current sample.
Without motion being triggered, the device only takes a Lux reading every 5 minutes, no matter what you configure for a reporting interval.
The device will immediately send a Lux event after it detects motion.
When motion goes inactive, the 5 minute sample timer starts, meaning if there's no further motion events, you'll get another Lux report in 5 minutes with a real sampled value.
OK, so if all the above weren't enough funk to make you start drinking today, here's the winner:
The device will respect configured Lux threshold reporting settings while the device is within the configured motion active window, so yeah...
If you set the motion timeout to five minutes (or just keep it active), then set the lux threshold to 1, it will indeed detect and report these levels of changes.
The motion active Lux report is not generated if the sensor value doesn't exceed the threshold set.
In other words, while motion is active the device respects the reporting settings, when it's inactive it defaults to a sample value updated every 5 minutes
Without a doubt the most bizarre implementation I've ever seen,
I'll need to digest all this for a bit so I can make the best use of this, but currently the Lux reporting options don't really align with the devices capabilities as you have noted.