Cleanup policy with "Last Downloaded Before" don't work

Hello,

I'm trying to configure a cleanup policy for my hosted raw "backups" repository.

I have one month and a half of backups and I want to have only one month, so if I set my cleanup policy to "Published Before: 30 days", it works (I can see the list of what's selected in the "Preview results"). But if I add the "Last Downloaded Before: 30 days" (or any value) to my cleanup policy, the preview returns nothing and when I run my cleanup policy nothing is deleted.

None of my backup stuff has ever been downloaded so I don't understand why Nexus doesn't select the old files.