macOS is trolling me. I need 30 GB free space, I have 10 GB free space before. I move 12 GB file to sd card, it said I have 25 GB free space now. And then I move 18 GB file to SD card, and after that it said I have 27 GB free space. That doesn’t add up .

And system information reported 75 GB free space with 25 GB purgeable space.