When you list events in a Collection, and try to serialize it through the REST API, you get the following error

{
  "message": "('Could not adapt', <Occurrence at /Plone/eu/agenda/pentsio-duinak-eskatzeko-elkarretaratzea/2024-09-16>, <InterfaceClass plone.app.contentlisting.interfaces.IContentListingObject>)",
  "type": "TypeError"
}

The point is that plone.app.event's Ocurrence objects are not IContentish and thus are not adaptable to IContentListingObject, so this line breaks.

The solution on plone.restapi's side should be to defensively call IContentListingObject and in plone.app.event's side to define an adapter for IContentListingObject.

PRs to come