In SDC - "Where workflow requires digital signatures on forms or on answer submissions, implementers SHALL make use of the Provenance resource to record such signatures." http://hl7.org/fhir/uv/sdc/security.html

conflicts with

 
SDC QuestionnaireResponse Profile supports sigs using the  http://hl7.org/fhir/StructureDefinition/questionnaireresponse-signature extension : http://hl7.org/fhir/uv/sdc/STU3/StructureDefinition-sdc-questionnaireresponse.html
 
Furthermore... SDC Questionnaire Profile supports http://hl7.org/fhir/R4/extension-questionnaire-signaturerequired.html.
 
which states:
"If this appears at the Questionnaire level, then the signature will be gathered for the entire form when it is marked complete. If it appears on a particular item, then it will be gathered on that question or group when it is filled in. (E.g. seeking the user's initials beside certain questions.)
The signature can be captured using the http://hl7.org/fhir/StructureDefinition/questionnaireresponse-signature extension."

(emphasis mine)
 

additionally this section suggests the signature is inline

"signatureRequired Questionnaire Questionnaire, group, question CodeableConcept example
This allows a form to indicate whether the form must be signed on completion or whether specified questions or answers themselves must be signed. If a signature is required, elements present in the QuestionnaireResponse must have signatures before marking the QuestionnaireResponse as complete. Signature can be as simple as providing the user's initials to confirm that they've verified and agree with the answer, or it could mean a full digital signature. This extension will tend to be used on Questionnaires that result in legal documents." http://hl7.org/fhir/uv/sdc/behavior.html
 
propose relaxing the SHALL to a MAY use Provenance or the http://hl7.org/fhir/StructureDefinition/questionnaireresponse-signature extension as enveloped detached signature where the questionnaire, group or item is the envelope.