Play for Today Vol 3 Reg B Disk 1

[PFT99]

Hello all - I've a been happy Makemkv user for a while now (since Redfox expired) but unfortunately have an annoying problem to report.

My usual MO is to make a backup to keep on an UNraid NAS and playback via a Duneplayer.

Play for Today Vol. 3 is a BFI UK release with three BDs. Discs 2 and 3 backup and play faultlessly, but Disc 1 is a consistent problem. It (the physical disc) plays without problem on my BD player but the backup refuses to play via the Duneplayer. It starts and displays the region banner but then stops with a blank screen.

There were no problems reported during the backup process (see next) nor in the log (attached).

MakeMKV v1.17.9 win(x64-release) started
Debug logging enabled, log will be saved as C:\Users\pftun/MakeMKV_log.txt
Using LibreDrive mode (v06.3 id=483A53F63141)
Backing up disc into folder "D:/Ripped DVDs for Tower2/TV Drama/TV Plays/Play for Today Vol. 3/Disc 1/PLAY FOR TODAY 3 D1"
DEBUG: Code 0 at 5o[KeC_%cwVJ\0Z+:29398070
Loaded content hash table, will verify integrity of M2TS files.
Backup done

Any help/guidance appreciated.

PS disc is clean, no visible defects and AACS is V76,

[PFT99]

Just wanted to add that D1 has many more mpls files (408) than either D2 or D3, which have seven each. Also D1 has the 'copy detected ' mts file (01984.m2ts), which neither D2 nor D3 have (either before or after backup).