Hidden units

[Mowgli]

I had another situation I didn't quite understand: As the sun rose (from a dawn turn to a normal turn, visibility increased from 2 to 4 hexes), I was immediately able to spot an enemy vehicle and gun unit positioned deployed in a village + bunker hex. I had the first turn, so they had no chance to fire at me yet (as I was the first to have the increased visibility). I found this odd, since village has a height of 3 so both should have remained concealed?

If the description is not clear, I can upload a video (I'm recording a Let's Play of the match).

Can it be that units who are not given any opportunity fire settings don't even "try" to conceal themselves and are thus automatically spotted?