What is the most appropriate action for a Scrum Master when a few developers consistently work with the Product Owner during backlog refinement?

The most appropriate action for a Scrum Master in this scenario is to recognize that if a few developers are consistently working with the Product Owner during backlog refinement, it could be an aspect of how the team operates that they have chosen for themselves. The Scrum framework promotes self-organization and encourages teams to find ways of working that best suit their needs.

This situation might indicate that some developers have taken the initiative to engage more deeply with the Product Owner, which can contribute positively to the refinement process. As long as this dynamic is not creating significant issues such as communication barriers or exclusion of other team members, the Scrum Master may decide that it is acceptable for the team to continue this way.

In such cases, it is important for the Scrum Master to assess whether the current dynamic is hindering team collaboration or transparency. If no negative impacts are noted, allowing the team to choose their collaboration method respects their autonomy and promotes a self-organizing culture.

If there are underlying issues or if it becomes evident that the teamwork is suffering as a result, the Scrum Master may then choose to facilitate a discussion with the team to explore the dynamics or encourage broader participation, but this should be based on observed effects rather than making assumptions about the working process.