I’m saying that there’s a limit in how many publishes you can make per second. That limit it documented as 1 per second, as mentioned by Rick as well. If you go over that limit, it will place you on a time-out until you get below the limit again. The loop runs extremely fast, so after that 500 millisecond delay, it will almost immediately publish again. Since 500 < 1000, you’re going over the limit, and thus will be rate-limited.
The sensitivity is mentioned to be EXTREMELY sensitive at 9000, and you’ve placed it at 1200. Again, 1200 < 9000 so it will be ridiculously sensitive to the point where I’m almost certain it would trigger randomly without actual movement.
As for the code formatting, it’s this one (which is the first hit if you search for those terms I mentioned…):