Just back from meeting - glad you sorted it. I think I know why some of yours work and others don't Some versions of the dotnet template for the extension has a MSBuild step in the CSProj which will build the client assets for you and Github Actions was doing this for you. But I reckon your on a newer version of the template where it got removed to avoid voodoo black magic - so yeh you need to explictly make sure your building the assets or if you liked the approach from before - add it back in your csproj to do the client build when you do a build of the .NET csproj