Castle disks give warning

[Woodstock]

I just acquired 5 season's worth of the series Castle, from an assumed-legitimate source (vendor in Amazon market place with several thousand ratings), but MakeMKV has complained on each one of them:

It appears that you are opening the disk processed by DvdFab/MacTheRipper which is known to produce damaged VOB files. Errors may follow - please use original disk instead.

Is it likely this is a false-positive detection (since these ARE the original disks), or should I be contacting Amazon?

[mike admin]

Please make a testdump of any (shortest) title from any such disc and send the link as described at /onlinehelp/testdump.html . BTW, are these discs CSS protected?

[Woodstock]

Dump files created, and two links will be sent to svq@makemkv.com for review.

According to the opening process, MakeMKV scanned at least 14 CSS sectors, but that isn't shown in the log.