Hi Eric,
Unfortunately, I’m not that familiar with React and Next to be able to tell you for sure. However, I did found this:
- Hydration failed because the initial UI does not match what was rendered on the server · Discussion #35773 · vercel/next.js · GitHub
- react-hydration-error | Next.js
Regarding Cloudflare, it seems that the client proxied the site through Cloudflare. Those have some possible drawbacks, but that really shouldn’t affect things…