$expand operation with ECL, "member of" syntax, reference set types

[JonZammit]

Inconsistent results when using $expand operation in combination with ECL, ^ "member of" syntax, and different reference set types.

Example 1) - query to expand 723264001 |Lateralizable body structure reference set|, a simple reference set type. This produces the expected results. 20,000+ members in expansion:

{{url}}ValueSet/$expand?url=http:https://snomed.info/sct?fhir_vs=ecl/%5E723264001

URI-decoded ecl query: ^723264001

Example 2) - query to expand 446608001 |SNOMED CT to ICD-O simple map|, a simple map type refset. Response indicates 0 concepts in expansion:

{{url}}ValueSet/$expand?url=http:https://snomed.info/sct?fhir_vs=ecl/%5E446608001

URI-decoded ecl query: ^446608001