When you back up a drive contaning bad blocks, then perform a bare-metal restore to a new drive and run a backup job, it will return this warning:
One or more bad blocks were detected and skipped
Windows stores information about bad blocks in a $BadClus metadata file. After performing a bare metal restore, $BadClus is not updated, so Windows still considers some blocks invalid.
Run chkdsk /b volume_letter to refresh the information about bad blocks.