Bug in the quick watch with object equal to empty string

Why the quick watch shows the statement p == "" as false, but we are going in the if statement.

    static void Main(string[] args)
    {
        string q = "";

        A(q);
    }

    static void A (object p)
    {
        if(p == null || p =="")
        {
            Console.WriteLine("Debugger shows false");
        }
    }