MDX query dimension properties generates OLAP storage engine errors

select 
	{[Measures].[POS Units]
	,[Measures].[Store On Hand Units]
	,[Measures].[Lost Sales Dollars]} on columns,
non empty
      [Item].[Consumer Product L3 - Sub-Category].members 
	  --[Item].[Consumer Product].[Sub-Category].members

	DIMENSION PROPERTIES PARENT_UNIQUE_NAME
	,[Item].[Consumer Product L3 - Sub-Category].[Consumer Product L3 - Sub-Category].[Category]
ON ROWS   
FROM [Customer Analytics] 

I have an MDX query that produces this error:

In the query, the item attribute is [Item].[Consumer Product L3 - Sub-Category], while the equivalent level in the hierarchy is [Item].[Consumer Product].[Sub-Category].

When I comment out the dimension property [Item].[Consumer Product L3 - Sub-Category].[Consumer Product L3 - Sub-Category].[Category], no error is produced. Or if I leave that property in, but I comment out [Measures].[Store On Hand Units] (which has a LastNonEmpty aggregation), no error is produced. If I use the level [Item].[Consumer Product].[Sub-Category] in the ON COLUMNS instead of the attribute, no error is produced.

Also, this query works without error in the QA environment, which has the same structure as the Production environment, where the error occurs.

I have done a full process on the Item dimension, which forces a full process of the partitions that the measure groups are a part of.

I have done a profiler trace on the query execution, to determine the difference between the execution with the attribute that fails, and the execution using the hierarchy level that doesn't fail. I do not see any difference in the events that are recorded by the profiler for these queries, except that the successful execution has one "Query Cube End" event after the "Query Dimension" event instead of an Error event.

How can I diagnose this issue? It appears to be some problem with the database files or the dimension files or something. Other than this obscure issue, the cube works fine.

Any ideas?

Mike