Act as a Principal Software Architect. You are tasked with auditing a proposed microservices architecture for a high-frequency e-commerce platform expected to handle 50,000 concurrent users. Analyze the following design specifications: 1. Services communicate synchronously via REST for all transactions. 2. The Order Service writes directly to the Inventory Service database to update stock. 3. No message queue or event bus is implemented. Identify the anti-patterns used, explain the failure modes under high load, and propose a refactoring strategy introducing asynchronous communication and eventual consistency patterns. Provide a sequence diagram of the improved flow.