Created attachment 140854 [details]
Generated K3b Debug Info log file from current Data Project failure.

Version:           20.04.2 (using KDE Plasma 5.18.6)
OS:                Linux

K3b Version: 20.04.2
Operating System: openSUSE Leap 15.3
KDE Plasma Version: 5.18.6
KDE Frameworks Version: 5.76.0
Qt Version: 5.12.7
Kernel-Version: 5.3.18-59.19-default
OS Type: 64-bit
Processors: 4 × AMD FX(tm)-4300 Quad-Core Processor
Memory: 30.0 GiB of RAM
Optical Drive:  PIONEER BD-RW   BDR-S08

SUMMARY

When producing a Data Project containing multiple boot ISO images on a blank Blu-Ray DVD DB-R medium, K3b fails to write to the /dev/sr0 device, which is the PIONEER BD-RW BDR-S08 Optical Drive. In detail the attached debug file reports the following main issue:

    cdrecord: Insufficient 'file read' privileges. You will not be able to open all needed devices.

which I have tried fixing this with:

    sudo chmod -R 777 /dev/sr0

However, it didn't correct the problem.

STEPS TO REPRODUCE
1. Create a Data Project.
2. Select several bootable ISO image files, (around 23.7GB total amount of storage required), using the Emulation Type as "Hard Disk" and select "Boot-info-table" from the Advanced Options Settings.
3. Click on Burn and select "Verify written data" from Settings and then click on Burn to begin burning the Blu-Ray DVD BD-R process.

OBSERVED RESULT

After about ten minutes burning process will fail and nothing will be written to the empty Blu-Ray DVD medium.

EXPECTED RESULT

Data Project would be continued and all of the bootable ISO images would be written to the empty Blu-Ray DVD medium, indexed without errors.

SOFTWARE/OS VERSIONS
Windows:  N/A
macOS:    N/A
Linux/KDE Plasma: OpenSUSE Leap 15.3/KDE Plasma 5.18.6
(available in About System)
KDE Plasma Version: 5.18.6
KDE Frameworks Version: 5.76.0
Qt Version: 5.12.7

ADDITIONAL INFORMATION
Using Verbatim Blu-Ray DVD BD-R blank medium.