Yes, this is likely the reason: https://support.apple.com/en-us/HT204015 https://support.apple.com/en-us/HT204015, and maybe (due to bug or by design) these sna

Yes, this is likely the reason: https://support.apple.com/en-us/HT204015 https://support.apple.com/en-us/HT204015, and maybe (due to bug or by design) these snapshots are enabled always, even if backup partition is not configured. > In macOS High Sierra, Time Machine stores snapshots on every APFS-formatted, all-flash storage device in your Mac or directly connected to your Mac. I'm curious how it's implemented? Does it use whole-filesystem snapshots? Some discussion: https://forums.developer.apple.com/thread/81171 https://forums.developer.apple.com/thread/81171