Urgent Debug Sprint for Async and Cache Issues in Real-Time Chat

Our real-time chat application has become unstable across both the User and Admin portals. The issue appears most clearly when sending messages. Core business logic has not changed, so we suspect a problem in asynchronous message handling or the caching layer, such as a race condition, stale cache, invalidation issue, or concurrency gap. We are not certain whether there were recent hosting or infrastructure changes.

What you will do
- Trace the message sending flow end to end, focusing on async orchestration and cache interactions
- Use logs, breakpoints, or profiling tools such as Redis monitor, Node.js inspector, or equivalent
- Identify and confirm the root cause with clear technical evidence
- Apply and commit a small, safe fix if possible (for example await misuse, cache invalidation, or locking adjustment)
- If the issue requires more than a quick patch, provide a clear and specific next step plan

Deliverables
- Concise technical report with problem summary, evidence, and resolution or next steps
- Patched source files or pull request if a minor fix is applied
- Recommendations for long-term stability and prevention

Notes
- Priority is speed, accuracy, and strict scope control
- No major refactoring. Surgical debugging only