I have a Subaru with assistive braking (EyeSight) and it does the exact same thing on a very specific off ramp. My best guess was that it's detecting the big yellow "turn" sign right before the loop. It's about big enough to be the back of a car to the primitive detection.

That's not a solution for you, just thought I would share commiseration. Your experience with it is slightly worse than mine has been but I leave mine on for the exact same reason.