How can Kruskal's algorithm return different spanning trees?
Cuts aren't made as part of Kruskal's algorithm; they are used in a proof that it always returns a minimum spanning tree. See e.g. here.

But you don't need them to answer the question in the title; instead, take as your graph a triangle with all 3 edges the same weight. Then any order on these edges is allowed and Kruskal's algorithm will return the tree consisting of the first 2 edges, whichever they are.