React Profile Page Bug Fix

My FastAPI + MongoDB project already runs smoothly on the back-end, but the User profile page on the React 19 front-end is misbehaving. I built the interface with React Router and shadcn/ui components; somewhere in that stack the page is rendering inconsistently and occasionally throws console errors that break navigation back to the dashboard.

Here’s what I need from you:
• Pinpoint the root cause of the User profile page issues (layout glitches, state not persisting, any runtime errors).
• Deliver clean, well-commented fixes in a pull request or patch, keeping to the existing code style.
• Verify the solution across modern browsers and confirm the route still works seamlessly with React Router.

You’ll have access to the Git repo, a brief tour of the component tree, and the mock API responses so you can reproduce the problem locally. Once the page is stable and error-free we can discuss an optional quick audit of the rest of the front-end, but for now the scope is strictly the User profile page bugs.