REST API does not return properties with Item datatype


I am using Release 15 and trying to GET all Properties of an Item using REST API with this request:


It does return all properties except the ones which are datatype = Item.

I am able to get the missing items properties one-by-one with such requests:


I tried with other ItemTypes as well and find same issue. 

Is this normal for OData or I am missing something in the API request? Or may be newer version has this issue fixed already?

Of course AML requests do return all properties though.