If your new Mac inherits your backup history
You can move the backup history from one Mac to another, but after the new Mac “inherits” the backup history, you can’t use the backup history on the original Mac.
You’re asked to specify whether you want a new Mac to inherit a backup if you do any of the following:
Use Migration Assistant to transfer your settings from an old Mac to a new one.
Use Migration Assistant to transfer your settings from a Time Machine backup of an old Mac to a new one.
Clone the disk you use to start up your Mac, or physically move it from an old Mac to a new Mac.
Replace your computer’s main logic board.
If you’re replacing an old Mac and want the new Mac to use the backups from the old one, click Inherit Backup.
If you plan to continue to use your old Mac, click Create New Backup to preserve the backup history and start separate backups for the new Mac.