Why a generic type definition implemented interfaces lose type information?

For example, if you run the following code...

Type IListType = new List<string>().GetType()
                                   .GetInterface("IList`1")
                                   .GetGenericTypeDefinition();

...and you watch IListType variable, you'll find that the whole Type instance has all properties available like FullName and others.

But what happens when you run the code bellow?

Type IListType2 = typeof(List<>).GetInterface("IList`1")

Now IListType got from a generic type definition isn't the same as the first code sample: most Type properties will return null.

The main issue with this is that IListType == IListType2 doesn't equal while they're the same type.

What's going on?