@Solla-topee 

@Mubz 

On my behalf, the battery level might have something to do (now also -12°C) but generally no.

I installed it now in normal, not inverted position, re-aligned a bit but basically no effect. Big items like cars or baby prams along the street are better detected, but persons coming across the view, some 6 meters away, are still not detected. 

With the latest firmware installed this week it is more stable, and detection zone works much better. We do have a lot snow which naturally makes things difficult. 

It could be the fresnel lens (assuming you are using it? Can't see through the cover...) which is poorly designed and cannot give enough distinction on IR sources movement. Any other PIR sensor works well over 10-12 m range. 

Also the PIR senses much wider than the camera view; I can go over the garage front to the mailbox (6-12m from cam) and see the LED lighting up just on the right edge, but either the zone set or some other reason it will not record anything. When coming back the same path, LED goes off and will not trigger anymore.

Wakeup sensitivity and motion sensitivity are at max (person, pet, vehicle is off).