Hey Neil!
I can confirm that there is some sort of dissruption occuring at the moment - up to version 2025.1, the out of the box Civil3d-nodes were very limited. Autodesk provided additional nodes via the Civil3d Toolkit.
Starting from version 2025.1, the Civil3d Toolkit is no longer maintained but a ton of its nodes (and many, many more) got moved the be available out of the box.
Unfortunately, some nodes didn’t “make the cut”, which is way a lot of people see their scripts failing at the moment.
See this post for further information.
There is a decent chance that you can update your script with the newly available nodes - if not I’m afraid you’ll have to stay within version 2024 or use code to accomplish 2024-behaviour.
Edit: If you post your dynamo graph or a screenshot of the failing nodes, I’m sure people are happy to help!