If you do a Second Observation, at a later Time, the developed MPO Density at that time will distribute the probability of where you will find it. The new Observation will start a development of a new Cloud, from the position where you now observed the MPO.
A Third Observation will in this way be dependent of whether or not you did the Second Observation. But this is not because you changed the MPO, it is because your Observation linked yourself with one possible part of its development.
You only have 3D of freedom, this only allows you to see slices of the Universe. And since Time is moving forward constantly this forces you to navigate the world by making choices. Hopefully reaching the slices of your future that you want to experience.