Set in the where clause causes the simple query to fail

Hi,

I have a very simple query (using Adventure Works 2012) that I am running against MSAS 2012. It fails with the infamous error "The MDX function failed because the coordinate for the 'ParentEmployeeKey2' attribute contains a set". However, in my case I don't really have any calculations referenced by the query that are trying to explicitly refer to the current member of any hierarchy. Here's the query:

with
  member measures.x as 1
select
  x on 0,
  [Employee].[Employee].[Employee].Members ON 1
from 
  [Adventure Works]
where
  {[Employee].[Employees].&[290], [Employee].[Employees].&[272]}

It's pretty easy to rewrite this query to get the desired results, but I am very confused why I am even encountering this error here. Product bug?