Use FinRunbook to analyze whether Lululemon’s September 2026 earnings deterioration reflects weaker consumer demand, product execution problems, or competitive share loss. Examine FY2021–FY2025 and the latest comparable interim periods, focusing on regional growth, comparable sales, inventory, markdowns, margins, and cash flow. Compare relevant disclosures from Nike, On, and Athleta, and include Alo and Vuori only where credible public data exist. Distinguish evidence of category weakness from evidence of customer switching; do not infer exact market-share transfers from competitor growth. Produce an English interactive financial report with a deterioration timeline, competitor comparison, and recovery scenarios.