This is reflected by the 0..0 cardinality of this element in the US profiles of Patient: issuers of SMART Health Cards in the United States SHALL conform SHCPatientUnitedStatesAD and SHOULD conform to SHCPatientUnitedStatesDM.

• Is that really intended to be a colon there?  It seems it should be a period and the bit about conformance should be a new sentence.
• "SHALL conform SHCPatientUnitedStatesAD" is missing "to" (i.e., "conform to")