Verify that both copies are inside selected accessible locations. Download cloud placeholders and keep external disks connected.
Open Settings → Scanning → Duplicate Files and confirm both files exceed the minimum size. Review ignore rules.
Files with the same name are not necessarily duplicates, and visually similar images are not identical content. Edited metadata or content can make copies different.
Test with two noncritical known-identical files in a small folder. If they are not grouped, record their formats, sizes, paths, and the scan settings.