Introduce method changes variable name incorrectly

Steps to reproduce:
1) have a code:
public class Test {
    
    String val;
    
    public void m(String val) {
        this.val = val;
        
        System.out.println(val);
        
    }
}

2) select 
        this.val = val;

   and introduce method from it

->
public class Test {
    
    String val;
    
    public void m(String val) {
        newMethod(val);
        
        System.out.println(val1);   // <---- val1 is not declared!
        
    }

    private void newMethod(String val1) {
        this.val = val1;
    }
}