What determines a duplicate? I’ve got an instance where Rafael Kubelik conducts two different orchestras (presumably on different dates) yet the two albums are deemed to be duplicate.
According to the Roon Knowledge Base:
Roon automatically looks for duplicate albums in your library. If any tracks or albums have similar artist and album info, and also have similar lengths, Roon considers them to be duplicates.
If it’s wrong, just click Remove From Duplicates.