Reflection Renders HashCode Unstable

In the following code, accessing the custom attributes of a SomeClass results in the hash function of SomeAttribute becoming unstable. What's going on?

static void Main(string[] args)
{
    typeof(SomeClass).GetCustomAttributes(false);//without this line, GetHashCode behaves as expected

    SomeAttribute tt = new SomeAttribute();
    Console.WriteLine(tt.GetHashCode());//Prints 1234567
    Console.WriteLine(tt.GetHashCode());//Prints 0
    Console.WriteLine(tt.GetHashCode());//Prints 0
}


[SomeAttribute(field2 = 1)]
class SomeClass
{
}

class SomeAttribute : System.Attribute
{
    uint field1=1234567;
    public uint field2;            
}