A major healthcare provider's implementation of a multi-agent AI system highlights the challenges and potential pitfalls in coordinating specialized agents for complex tasks, such as patient diagnosis. In a critical case, a failure in information exchange between agents led to a misdiagnosis, demonstrating how coordination failures can cause AI systems to produce hallucinations—outputs that are confidently incorrect. The article examines the causes of these failures, such as architectural limitations, distributed state management challenges, and rigid communication structures, which can lead to knowledge inconsistencies, task boundary confusion, and communication protocol breakdowns. To mitigate these issues, the text suggests strategies like cross-agent consistency validation, clear information flow architectures, joint training and alignment techniques, and formal verification methods. The article also emphasizes the importance of comprehensive evaluation and monitoring tools, illustrated by the Galileo platform, to ensure robust coordination and prevent hallucinations in multi-agent systems.