You can see the release planning there, and for NC28.0.2 there is a release candidate already out there:
where you can see what was fixed.
With such a detailed error description …
In the admin section, it also shows warning and recommendations, often with links to the documentation. A few things are mainly to improve performance and configuration, not that there is really something broken.
If there are errors, it can help to look for them specifically and try to fix them.
Good, you do backups.
This can help if you know that something went wrong and you revert to before that happened. We have also people here that say I have installed it 5 times and every time it breaks. Perhaps it breaks for everybody and it is just bad, or there is a problem with their installation method.
External storage can be a bit tricky, it adds another layer and the files are transferred between the server and the storage backend, so it can fail on two points, or in between…
When you see bugs in the bug tracker that are similar to yours that will be in the next release, there is a strong chance that it will improve. Or if it was working in a previous version, after the upgrade it doesn’t work any more, then it might be fixed (if someone else had the same error, reported it to the bug tracker and the bug was fixed).