For Audio CDs the verify "asks" the drive to read all tracks/sectors of the disc, therefore, it fully relies on the drive's abilities to report errors/bad sectors.
As for your NEC drive, it may be too old to undestand the MMC standard commands that ImgBurn uses. If I recall correctly another user also had problems using ImgBurn to read CDs on an old Plextor SCSI CD-ROM drive.