To create a societal change towards a sustainable future, constructive relations between science and policy are of major importance. Boundary organizations such as the Intergovernmental Panel on Climate Change (IPCC) have come to play an important role in establishing such constructive relations. This study contributes to the development of empirically informed knowledge on the challenge of balancing different expectations for how the science–policy relation is to be constructed to create trustworthy knowledge and policy decisions, i.e., when to be what and to whom. This study revisits Climategate and uses the public debate on the IPCC’s credibility, legitimacy, and policy relevance that followed Climategate as an analytical window to explore how the IPCC balanced the science–policy relation in a trustworthy manner. The analysis is based on a document study. The study shows how different expectations on the science–policy relation coexist, and how these risks create a loss of trust, credibility, legitimacy, and policy relevance. Thus, for boundary organizations to have a chance to impact policy discussions, reflexivity about the present epistemic ideals and expectations on knowledge production is of major importance, and must be reflected in an organizational flexibility that is open to different strategies on how to connect science and policy in relation to different actors and phases of the knowledge production process.