What steps will reproduce the problem?
1. Compile and run

package main

import (
      "fmt"
      "reflect"
)

func main() {
      x := string("hello")
      v := reflect.ValueOf(&x).Elem()
      oldvalue := v.Interface()
      v.SetString("world")
      newvalue := v.Interface()
      fmt.Println(oldvalue, newvalue)

      n := int64(1)
      v = reflect.ValueOf(&n).Elem()
      oldvalue = v.Interface()
      v.SetInt(2)
      newvalue = v.Interface()
      fmt.Println(oldvalue, newvalue)
}

What is the expected output? What do you see instead?

Expected:
hello world
1 2

Seen (GOARCH=386):
world world
2 2

Seen (GOARCH=amd64):
world world
1 2