The definition of Interfaces requires that any element a resource defines that exists in the interface uses a compatible definition.

In MedicationKnowledge there are several violations:

• MedicationKnowledge.name is an array (0..*), while CanonicalResource.name is a scalar (0..1).
• MedicationKnowledge.status has a required binding to a different value set than the required binding on CanonicalResource.status
• MedicationKnowledge.author is of type Reference, which is incompatible with MetadataResource.author (type ContactDetail)

These requirements were not caught by tooling (a recent ticket to FHIR-I is addressing that), but it will be corrected in the future. Filing this ticket so that the resource definition can be corrected prior to failing the build.