Auto high beams don’t work on unsealed roads/unknown speed zones?

[Nuclear Fusion]

Had an interesting experience this evening (Australian time) - auto high beams were working fine as usual (they work really well), but not long after I started driving on an unsealed road, the high beams switched off & wouldn’t come back on again (no cars around). I rebooted but it didn’t fix. Then after 10 minutes or so I got backed to sealed road & they started working again.
I don’t know if it was the road being unsealed or that the speed zone wasn’t registered - I’m guessing the latter. But even if it was due to being an unknown speed zone, what’s the justification for low beam only lights?

 

[strykeroz]

Perhaps the bright reflection off the gravel road registers as oncoming lights? I like to drive with high beam when possible in the suburbs as we still have critters to avoid late at nights (the odd wallaby, possums, cats...bandicoots & koalas on occasions) and I found it kept dipping when there was street lighting ahead so that's one auto feature I've turned off tbh.