I think I understand you're using the Apple SuperDrive. (https://www.apple.com/shop/product/MD56 ... superdrive) That works with CDs and DVDs. I haven't used this particular drive with MakeMKV before… have you tried shutting down MakeMKV, unplugging the drive from your Mac waiting a few seconds and plugging it back in? Unplugging the drive will remove power to the drive; when you plug it back in, the drive will essentially 'cold boot', which can occasionally be helpful.
Also, in MakeMKV's preferences, on the General tab, in the Miscellaneous box, make sure 'Log debug messages' is checked. Give one of your problematic discs a go and post the log here. That'll help us know more precisely what's going on.