'Sleep Has Her House' getting 'DEBUG Code 0' and 'failed to open disc'

[sidetracked]

This is a BD-R produced by the filmmaker and sold on their website.
It plays fine on multiple different drives, including the one I'm trying to use for the back-up.

But when I try to have Make MKV start reading the disc, it shuts down within a second, and the debug log shows:
Using LibreDrive mode (v01.0 id=2D22701B6D8C)
Using direct disc access mode
DEBUG: Code 0 at q||&e6 zKb*Tq,"Z:121267500
DEBUG: Code 0 at q||&e6 zKb*Tq,"Z:121263682
DEBUG: Code 0 at q||&e6 zKb*Tq,"Z:213131341
Failed to open disc

Cleaned the disc a couple of times, tried an older, alternate drive, but nothing. Have copied other discs before and since with no problem.

Because this is a BD-R, so many not last as long I'd love to be able to make a back up, but never seen anything quite like this in many hundreds
of MakeMKV rips.

Any thoughts or suggestions would be most appreciated!!