PMP Practice: Recommend a Project Execution Strategy

Björn Magnússon is leading an agile project at Ikigai Automation to develop a multiplayer mobile game. The team is three sprints into a planned ten-sprint release. During the latest sprint review, stakeholders from the marketing department express frustration that the game's core social features—initially scheduled for Sprint 5—are not yet visible. They argue these features are critical for upcoming promotional activities and want them prioritized immediately. However, the development team has been focusing on foundational game mechanics and infrastructure, which they believe must be stable before adding social features. The product owner agrees with the developers' technical sequencing but is concerned about marketing's business needs. Velocity has been stable at 32 story points per sprint, and the team has successfully delivered all committed work so far. What should Björn do to address this situation?