Hey, when you say your location is "Canada", I figure you're right in the middle of the word, on a map.
That would put me in Winnipeg, the geographical centre of Canada and the flattest part of the Prairies.
Happens all the time and is well documented in PC. Has to do with the VSC (vehicle stability control) and other protection circuits that prevent over-torque of the drive shafts(s) by the electric MG's. You have to watch the road for these irregularities, or know about them in advance so you can avoid or carefully brake. I always allow a sizeable following distance between me and the car ahead just in case. It's a Prius thing.
I usually just "pat" it down if approaching a light that might change. Each "pat" reduces the speed 1 mph. I see no problem with holding it down except cruise control stops working under 23 mph. I am OK with braking too. As for following traffic, I drive using the rear view mirror a lot. Often I'll see some assh*le tailgater but that is something else. Bob Wilson
There was 'brake pause' problem we learned about in the first year. After a bit of investigation, we were able to reproduce it at will but it would surprise those not used to it. There is a Toyota patch a dealer can apply that fixes the problem. Bob Wilson