Publication Build: This will be filled in by the publication tooling
Both items refer to preadopted R5 elements: the link points to an non-exiting element in R4 FHIR specifications.
Future version of the FHIR IG Publisher tool should fix this issue.
The Laboratory Certified Reference Material value set includes concepts that are derived from systems not having canonical urls assigned and/or confirmed by HL7 yet.
Adopters should use these urls being aware that they may change.