Are you saying you want to delete/ignore issues about duplications in code? If so, you can simply mark them Won’t Fix via the Issues UI. Or you can remove that rule from your profile.
If you’re instead talking about other types of issues that are raised twice, some detail on the issues themselves will be needed.
That UI is SonarQube. Go to the issue in the project’s Issues tab, and if you have the Administer Issues permission on the project, you’ll be able to mark the issue False Positive or Won’t Fix.
These aren’t “issues” so you can’t mark them False Positive or Won’t Fix. The only way you can address them is to remove the duplications. Either that, or set duplication exclusions so that the files aren’t included in duplication detection.
I’m having the same problem, however I don’t have access to [Project Homepage] → Project Settings → General Settings → Analysis Scope → Duplication Exclusions.