Cross-project duplication detection is a deprecated feature. Hence, when it is used, we show a warning in the scanner logs, as well as on the project overview:
This can be activated at the global level, which will enable it for all projects. However, we can override this per project. When cross-project duplication is activated at global level, but deactivated at project level, SonarQube still issues a depreciation warning for the analyzed project. This is incorrect, as the duplication is indeed not being computed for this project. We should not show these warnings in these cases.