self_link for Jsonapi::V1::ProjectResource.comments(ToMany) could not be generated

This issue is a (choose one):

• Problem/bug report.
• Feature request.
• Request for support. Note: Please try to avoid submitting issues for support requests. Use Gitter instead.

Checklist before submitting:

• I've searched for an existing issue.
• I've asked my question on Gitter and have not received a satisfactory answer.
• I've included a complete bug report template. This step helps us and allows us to see the bug without trying to reproduce the problem from your description. It helps you because you will frequently detect if it's a problem specific to your project.
• The feature I'm asking for is compliant with the JSON:API spec.

Description

I get a bunch of warnings that look like this:

self_link for Jsonapi::V1::ProjectResource.comments(ToMany) could not be generated

but there's no indication of what I've done to cause them or what I could do to resolve it.

Beginne mit der im Issue verlinkten Rails 5-Bug-Report-Vorlage und erstelle eine minimale Reproduktion für die Warnung zu Jsonapi::V1::ProjectResource.comments(ToMany). Verfolge, wie der self_link dieser Beziehung generiert wird, und halte den fehlenden Kontext fest, der zur Erklärung der Warnung erforderlich ist. Als erledigt gilt die Aufgabe, wenn die Ursache und eine konkrete Lösung festgestellt und durch eine geeignete Regression-Prüfung abgedeckt sind.