@Eric could you share the log file for the MSBuild step please?
There’s nothing obviously wrong in the logs for the “analyse” step, and it looks like the C# analyzer report files are being produced. However, it looks like the analyzers are not reporting any issues, so it would be useful to see what is actually passed to the csc.exe command line.
One possibility is that the RunAnalyzersDuringBuild property is false - see this thread for more info.