The expansion of the value set Iso 3166 Part 1: 2 Letter Codes from the core FHIR specification has the following compose element:
Which is intended to include all concept where the code value is 2-characters long.
However, the expansion generated by tx.fhir.org is also including the concepts that have 3-character codes. See here
This suggests that the "[A-D]{2}" regular expression is not being correctly processed by the server.
The expansion of the value set Iso 3166 Part 1: 2 Letter Codes from the core FHIR specification has the following compose element:
Which is intended to include all concept where the code value is 2-characters long.
However, the expansion generated by tx.fhir.org is also including the concepts that have 3-character codes. See here
This suggests that the "[A-D]{2}" regular expression is not being correctly processed by the server.