Archived - Mac OS X 10.5: Time Machine performs full backup after a full restore
After performing a complete restore of a Mac from a Time Machine volume, Time Machine may perform a full backup the next time it backs up.
This is normal. Time Machine will resume incremental backups after the full backup has completed.
If you want to view your previous backups, Control-click or right-click the Time Machine icon in your Dock or Option-click the Time Machine menu extra and Choose "Browse Other Time Machine Disks," then select your previous backup volume. You will enter the Time Machine where will you be able to browse your previous back ups and restore files.