DVD release hard to "dvdunauthor"

[eblanca]

I have this DVD I tried to unauthor but dvdunauthor (git master) seems to face some troubles.
The environment is my debian stable box, x86_64 with libdvdread-6.0.1
The extraction begins with some minutes of fast seeking operations, then the actual copy starts very slowly till it ends up with an mpeg2 stream corrupted in several points.
On the other side, vlc 3.0.12 plays this disc flawlessly (main menu, extras, movie and all). I thought vlc used the very same libdvdread for dvd disc access but perhaps this is not true...
Anyway, this disc is a Columbia Pictures release from 2007 and two early releases from them are handled by dvdunauthor without any issues (maybe they implemented a shiny new protection system in the meanwhile?).
I would like to help finding out what the problem may be, so I am willing to provide more data if needed.

[eblanca]

Log from dvdunauthor:
https://0x0.st/-oeC.log

[eblanca]

Log from vlc command line messages:
https://0x0.st/-o2i.log
Indeed, vlc calls libdvdnav which in turn calls libdvdread, and some of the error messages are similar.