Sustaining open source (OS) communities is fundamental to the long-term success of any open source software (OSS) project. An OSS project consists of a community of software developers who are part of a larger business ecosystem involving hardware and software companies. Peer review of software code, known as patch review comments, is an important quality assurance activity for OSS development that requires developers to provide feedback concerning their degree of satisfaction. Despite the importance of feedback, which can affect sentiment of OS communities, the underlying discourse has not been studied. In this study, we use Activity Theory to identify and categorise 20,651 discursive manifestations of contradictions that occurred in patch review comments of a large, evolving OS community. Unique community-specific expressions are identified and mapped to developers' sentiment during a software release cycle. The study contributes new insights concerning discursive manifestations of contradictions as a driving force for sustaining OS communities.