Create the classes:

public class A {
  public int k(long l) {
    return 1;
  }
  public int m() {
    return k(2);
  }
}
public class B extends A {
  public int k(int i) {
    return 2;
  }
  public int test() {
    return m();
  }
}

apply the push down method refactoring to m 

public class A {
  public int k(long l) {
    return 1;
  }
}
public class B extends A {
  public int k(int i) {
    return 2;
  }
  public int test() {
    return m();
  }
  public int m() {
    return k(2);
  }
}

The transformation changes behavior. After the transformation the test method returns 2 instead of 1