Internal error: An unexpected error occurred (file 'mdmodelmd.cpp', line 2669, function 'MDModelMD::DecodeRelAttr').

Hello,

When I execute the following MDX query, I get this error:
Internal error: An unexpected error occurred (file 'mdmodelmd.cpp', line 2669, function 'MDModelMD::DecodeRelAttr').
What does this error mean and how can I avoid this?

The intent of the query is to obtain a table like this:

*The query results are sorted afterwards.

WITH  
  
// top  
  
SET top_category AS TOPCOUNT( [Product].[Category].[Category].Members, 2, [Measures].[Order Quantity] )   
  
SET top_subcategory AS GENERATE(  
	top_category,  
	TOPCOUNT( ([Product].[Category].CurrentMember) * [Product].[Subcategory].[Subcategory].Members, 2, [Measures].[Order Quantity] )  
)   
  
SET top_product AS GENERATE(  
	top_subcategory,  
	TOPCOUNT( ([Product].[Category].CurrentMember, [Product].[Subcategory].CurrentMember) * [Product].[Product].[Product].Members, 2, [Measures].[Order Quantity] )   
)   
  
// all  
  
SET all_category AS {[Product].[Category].[All Products]}  
  
SET all_subcategory AS top_category * {[Product].[Subcategory].[All Products]}  
  
SET all_product AS top_subcategory * {[Product].[Product].[All Products]}  
  
// other  
  
SET all_category_ AS [Product].[Category].[Category].Members   
MEMBER [Product].[Category].[other_category] AS AGGREGATE( all_category_ - top_category )  
SET other_category AS [Product].[Category].[other_category]  
  
SET all_subcategory_ AS top_category * [Product].[Subcategory].[Subcategory].Members  
MEMBER [Product].[Subcategory].[other_subcategory] AS AGGREGATE(  
	EXISTS(all_subcategory_,([Product].[Category].CurrentMember))  
	- EXISTS(top_subcategory,([Product].[Category].CurrentMember))  
)  
SET other_subcategory AS top_category * [Product].[Subcategory].[other_subcategory]  
  
SET all_product_ AS top_subcategory * [Product].[Product].[Product].Members  
MEMBER [Product].[Product].[other_product] AS AGGREGATE(  
	EXISTS(all_product_,([Product].[Category].CurrentMember, [Product].[Subcategory].CurrentMember))  
	- EXISTS(top_product,([Product].[Category].CurrentMember, [Product].[Subcategory].CurrentMember))  
)  
SET other_product AS top_subcategory * [Product].[Product].[other_product]  
  
  
SET final AS   
top_product  
+ all_category * {[Product].[Subcategory].[All Products]} * {[Product].[Product].[All Products]}  
+ other_category * {[Product].[Subcategory].[All Products]} * {[Product].[Product].[All Products]}  
+ all_subcategory * {[Product].[Product].[All Products]}  
+ other_subcategory * {[Product].[Product].[All Products]}  
+ all_product  
+ other_product  
  
SELECT  
	[Measures].[Order Quantity] ON 0,  
	NON EMPTY final ON 1  
FROM  
	[Sales]  

In the final set, it seems this line is not working well with others.
Excluding it from the query returns results.
What can be the alternative for the grand total?

+ all_category * {[Product].[Subcategory].[All Products]} * {[Product].[Product].[All Products]}  

What is confusing is that this line works well by itself like this.

SET final AS all_category * {[Product].[Subcategory].[All Products]} * {[Product].[Product].[All Products]}  

Also, if I query only category and subcategories, there isn't any error.

WITH  
  
// top  
  
SET top_category AS TOPCOUNT( [Product].[Category].[Category].Members, 2, [Measures].[Order Quantity] )   
  
SET top_subcategory AS GENERATE(  
	top_category,  
	TOPCOUNT( ([Product].[Category].CurrentMember) * [Product].[Subcategory].[Subcategory].Members, 2, [Measures].[Order Quantity] )  
)   
  
// all  
  
SET all_category AS {[Product].[Category].[All Products]}  
  
SET all_subcategory AS top_category * {[Product].[Subcategory].[All Products]}  
  
// other  
  
SET all_category_ AS [Product].[Category].[Category].Members   
MEMBER [Product].[Category].[other_category] AS AGGREGATE( all_category_ - top_category )  
SET other_category AS [Product].[Category].[other_category]  
  
SET all_subcategory_ AS top_category * [Product].[Subcategory].[Subcategory].Members  
MEMBER [Product].[Subcategory].[other_subcategory] AS AGGREGATE(  
	EXISTS(all_subcategory_,([Product].[Category].CurrentMember))  
	- EXISTS(top_subcategory,([Product].[Category].CurrentMember))  
)  
SET other_subcategory AS top_category * [Product].[Subcategory].[other_subcategory]  
  
  
SET final AS   
top_subcategory  
+ all_category * {[Product].[Subcategory].[All Products]}  
+ other_category * {[Product].[Subcategory].[All Products]}  
+ all_subcategory  
+ other_subcategory  
  
SELECT  
	[Measures].[Order Quantity] ON 0,  
	NON EMPTY final ON 1  
FROM  
	[Sales]  

Thank you for your help on this!

SSAS Version: 14.0.6.443