Query not returning matches for combined (AND) enum list attributes

Using RTC 4.0.0.1, I found that queries do not return matches for combined (AND) enum list attributes

- steps to reproduce:
- create a PA - SCRUM
- create 2 enums - example: Product and Version - with 3 values
- create 2 attributes - enum list type
- add presentation
- save
- create a couple of work items - set Product and Version with various values
- create a query: add Product and Value
- select some value for each attribute - example: Product = P1, Version = V2
- run the query
expected: match found
observed: no match found

- variation : if you use type = enumeration, then query works fine

Is this a defect?