It depends on the value you’re putting in both maps, and how you’re referencing it there. For primitives, i.e stable let x = 5 it’s pass by value, but if you’re referencing an object (i.e. array/map) the reference is passed. So in that case updating the value in one data structure would also update the value that it’s referenced at elsewhere.
Here’s a basic example you can deploy and play around with.