It only happens on Commander and Legendary. But yes, patrols will consistently path directly into a flank on your concealed squad, they have metaknowledge.
On an unrelated note, just ran my first Haven defense mission. Went in with six, came out with five, two managed to go uninjured. It turned into a bit of a clusterfuck because literally all of the resistance members were hidden in a tiny corner of the map that prevented me from meta-spotting them through the fog, so I figured they were supposed to be placed when Firebrand returned to the AO. So I killed ayys for eight turns, Firebrand came back, I wondered what was up. Sent a scout out to search. Found them all at ~turn 14, killed the Faceless. But by then the reinforcements were mostly Mutons, Sectoids, and Vipers. I scrambled everything back in a fighting retreat.
Would have gotten away with 8/11 and the entire squad but my grenadier got disoriented and mind-controlled, and by that point there were ~30 active enemies on the battlefield. Still, a capture is better than a death, and I killed a shitload of ayys while getting the bulk of the resistance out. And got rid of that goddamn supply-leeching Faceless. Feels about right for a mishandled defense on Commander.