The spec notes that the Referral Task goes through multiple state and in fact, it looks like the Referrer and the Recipient can update Task as well as the patient who could accept the service?  It would help to see examples for each state of the Task with a discussion of the progression.  Not showing that is hiding an important part of Task functionality and alot of people learn by reviewing examples.  And each example should show important fields like last updated, status, and version id changing.  the accepted and completed example have last updated and version id matching.