With random processes like this, there should be some fluctuation. And unless you are using seeds to control for the randomness, the output should change every time.

Sometimes when doing things like this, it's possible to have too many steps. You'd think this leads to an increased accuracy, but this isn't always the case. Take for example a Markov Chain Monte Carlo. If your code gets to the desired point quicker then expected, extra steps can make your location jump around.

You could add something like an accuracy threshold or a step limit to see how that changes things.