Various issues exist in the 1.4 specification and the AOM regarding the constraint of existence of attributes, cardinality of container attributes and occurrences of classes within these containers.
These are discribed in the Developers' Wiki which concentrates on an issue with existence.
It does mean that default values for these constraints, mentioned in the ADL specification in the case of existence or provided in the reference ADL parser, cannot be assumed to be correct as they may not be consistent with the openEHR reference model.