Rubric Used in Assignment Not Found in the Parent Course

[test]

I'm using the Canvas API to pull data for a specific course. When I retrieve the assignments using the endpoint "/api/v1/courses/:course_id/assignments", one of the assignments has a rubric_id associated with it.
However, when I try to fetch the rubric details using the endpoint "/api/v1/courses/:course_id/rubrics/:id", I'm unable to find that rubric in the course.
Has anyone experienced this before? How can a rubric be linked to an assignment in a course if it doesn't seem to exist within that course's or account rubrics?

[stimme]

@test This post appears to be superseded by what you posted a few minutes later.