Hi guys,
Baris from NodeBB here, glad to see Opera is using NodeBB!
We just fixed the issue with the reply notification email not pointing to the correct post. https://github.com/NodeBB/NodeBB/issues/6027. It will be available in our next release.
If you discover more issues feel free to open issues on our github tracker. https://github.com/NodeBB/NodeBB/issues
Thanks.