Why toFixed() in Javascript acts like that?

Question

In this example/behaviour is something very strange.

Why does the function toFixed for the first two examples work and for this last one not?

    //example 1
    var num = 554.956;
    var n = num.toFixed(2)
    console.log(n);
    var num2 = 554.955;
    var n2 = num2.toFixed(2)
    console.log(n2);

    //output 554.96 and 554.96

    //example 2        
    var num5 = 5.956;
    var n5 = num5.toFixed(2)
    console.log(n5);
    var num6 = 5.955;
    var n6 = num6.toFixed(2)
    console.log(n6);

    //output 5.96 and 5.96
    
    //example 3
    var num3 = 55.956;
    var n3 = num3.toFixed(2)
    console.log(n3);
    var num4 = 55.955;
    var n4 = num4.toFixed(2)
    console.log(n4);
    
    //output 55.96 and 55.95

Related to: php round vs javascript toFixed

EDIT: about the duplicates especially this one: toFixed function not working properly ( please give a reason not an alternative)

The answer is very good and helps me to understand the difference between x.955 and x.956, but doesn't answer why this happens only to the 55.955 in my example and not to the 5.955 or 554.955.