The HQMF files available from USHIK, e.g. Stroke2 ( with id 40280381-446b-b8c2-0144-9e6e127929e3) are not actually in HQMF R2.0 (or R1) format.
Specifically, while they resemble R2 more than R1, they lack the specialized element names required of R2 (such as initialPopulationCriteria, measureDescriptionSection, allTrue), and instead have elements from CDA (such as conjunctionCode, sourceOf and observation).
This may be related to this blog post: http://motorcycleguy.blogspot.com/2011/11/greening-hqmf.html