How to delete old and stuck local time machine snapshot from one year ago
It is not possible to delete those orphaned Time Machine snapshots from the regular user space. You need to follow this steps to delete the folders:

Turn on your Mac and immediately press and hold keys Command (⌘) and R. Need help? (see About macOS Recovery)

Once you are in recovery mode, open from the menu Utilities &gt; Terminal.

In terminal you need to switch to your regular main HD. e.g. cd /Volumes/Mactintosh HD/.

Check if folder com.apple.TimeMachine.localsnapshots contains the orphaned snapshots. (if not you need to go back to /Volumes and find the right volume.

Go back to the HD folder from step 3.

Delete the folder rm -rf com.apple.TimeMachine.localsnapshots