Thanks. I tried CloneDVD, but couldn't find an actual download link for DVDShrink.
I bought an ASUS SDRW-08U9M-U USB DVD drive to test out a different brand and still have the same problem with both discs with AnyDVD, MakeMKV, WinX DVD, and CloneDVD. Setting the options to remove the menus doesn't work either, unfortunately.
I think it just comes down to mastering errors, which is unfortunate as these are the only two discs out 65 of the entire Masters of the Universe Collection that I own that can't be backed up.
If anyone would be willing to try on their system, I'd happily send the discs.