This is interesting. I have about six different routes I take when I walk from my house. I try to keep things mixed up and interesting. There are times when my dogs have “suggested” which way they want to go but never consistently like your lab has. Dogs do love routine but variety is nice, too. Looks like your pup has found the best combination of the two.
My dogs “help” me with laundry. Today is my typical day to run a big load. My boy picked up an item from the laundry basket as if to say, “isn’t today laundry day?”. Honestly, I don’t think he knew it was laundry day and more likely to have seen some physical cue from me. Perhaps I looked at the laundry basket a bit longer than usual. ( I will admit the dogs seem to have an uncanny sense of time, though)
So watch your body language when you get to the corner. Could you be offering a clue without realizing it?