Happened 2 times.
I am kneeling, static on the side of a road, gun raised, not moving. A bot crosses the street 50-60 m from me. I decide not to shoot. It is focused, gun raised, aiming straight in front of itself. The bot walks a few meters, detects me (his head's direction has not changed at all. It is still looking 90 degrees to me), then rotates and starts firing at me.
Given the circumstances I think it should not detect me.
It may be scanning left and right, but its head was not moving. If it were I could take decision about it and, for example open fire.