Background: Despite literature recognising the huge potential of co-production as a positive approach to evidence creation, there is a dearth of evidence about how co-production principles can problematise knowledge exchange, specifically in evaluation work. Aims: To critically examine three evaluation projects commissioned by voluntary sector stakeholders to illustrate challenges in knowledge exchange linked to the co-production of evidence exchange. Methods: We critically compare the challenges experienced in co-producing evidence across three evaluations, reflecting on power dynamics, co-productive ways of working and emotions, which all impact upon successful knowledge exchange. Findings: In Project 1, internal monitoring data required for reporting was not shared. In Project 2, the commissioners' need to evidence success resulted in limited knowledge sharing, with valuable learning about partnership issues and service delivery held internally. In Project 3, evidence demonstrating the failure of a local authority model of area management for community members was partially discredited by statutory stakeholders (state actors). Discussion and conclusions: Bias in evaluation reporting and academic publication can arise from current knowledge exchange processes, including co-production. Voluntary sector funding is problematic as stakeholders delivering programmes also commission evaluations. Knowledge exchange is influenced by vested interests arising from the political context in which data is gathered. Evaluators can face aggression, challenge and unfair treatment resulting in damaged relationships, and failures in knowledge exchange. The emotional elements of knowledge exchange remain under-reported. Varying and shifting power dynamics also limit knowledge exchange. Changing research practice, to support power sharing, needs further exploration to facilitate improved knowledge exchange.