After running the system on the topic "impact of AI on creative industries," you observe that each subagent completes successfully: the web search agent finds relevant articles, the document analysis agent summarizes papers correctly, and the synthesis agent produces coherent output. However, the final reports cover only visual arts, completely missing music, writing, and film production. When you examine the coordinator's logs, you see it decomposed the topic into three subtasks: "AI in digital art creation," "AI in graphic design," and "AI in photography." What is the most likely root cause?