Fix Unpredictable React Button Bug

My production site is built with React on the client side and a Node-Express API behind it. One part of the UI—specifically the buttons and form controls—is behaving unpredictably: clicks occasionally fire twice, form state jumps around, and sometimes nothing happens at all. I need someone to dive into the React code, track down the root cause, and implement a clean, test-covered fix without breaking any other components.

The stack in play is React 18, plain JavaScript (no TypeScript), Express 4, and Node 18. Most logic is in functional components that use hooks, so please be comfortable debugging useEffect / useState timing issues, event propagation, and async calls that hit the Express routes. If the issue originates in the API layer you’re free to patch that as well, but my priority is restoring predictable client-side behaviour.

Deliverables
• Isolated explanation of the fault (one-paragraph summary or commented code)
• Patched code committed to my Git repo via pull request
• Quick regression test or reproducible steps that prove the issue is resolved

I can give you repo access and a short Loom video that shows the glitch in action as soon as we start. Let me know your estimated turnaround time and any clarifications you need.