Cañon City - S12-E1
Continuity mistake: Sam and Luka are driving to Colorado, presumably in a hurry, to try to find her missing son, Alex. While their driving in the daytime, you can notice inconsistencies in the traffic and road. They are driving on the interstate, but getting passed up by semi trucks. The trucks are not slowly passing them either. It's almost as if they are stopped and the trucks are whirring past them. Then in one shot you see a car change to the left and start to pass, but when the camera angle changes, you see Sam passing up a semi truck at a high rate of speed. A moment later, as their still chatting, an exterior shot of the car shows them changing to the left lane to pass a truck, however the lines in the road are yellow, meaning they are not on the interstate anymore.
Answer: It was in "Chaos Theory", the first episode of season 9 (time code 00:13:55).
Super Grover ★