SOLVED: Playback issues with certain files

[Schos]

Not sure which exact model (I am not at home right now)
But some basic information:

$ sudo lshw -C display
  *-display
      description: VGA compatible controller
      product: Iris Plus Graphics 640
      vendor: Intel Corporation
      physical id: 2
      bus info: pci@0000:00:02.0
      version: 06
      width: 64 bits
      clock: 33MHz
      capabilities: pciexpress msi pm vga_controller bus_master cap_list rom
      configuration: driver=i915 latency=0
      resources: irq:129 memory:db000000-dbffffff memory:90000000-9fffffff ioport:f000(size=64) memory:c0000-dffff

$ lscpu
Architecture:                        x86_64
CPU op-mode(s):                      32-bit, 64-bit
Byte Order:                          Little Endian
Address sizes:                        39 bits physical, 48 bits virtual
CPU(s):                              4
On-line CPU(s) list:                  0-3
Thread(s) per core:                  2
Core(s) per socket:                  2
Socket(s):                            1
NUMA node(s):                        1
Vendor ID:                            GenuineIntel
CPU family:                          6
Model:                                142
Model name:                          Intel® Core™ i5-7260U CPU @ 2.20GHz
Stepping:                            9
CPU MHz:                              699.998
CPU max MHz:                          3400.0000
CPU min MHz:                          400.0000
BogoMIPS:                            4399.99
Virtualization:                      VT-x
L1d cache:                            64 KiB
L1i cache:                            64 KiB
L2 cache:                            512 KiB
L3 cache:                            4 MiB
NUMA node0 CPU(s):                    0-3

$ free -h
              total        used        free      shared  buff/cache  available
Mem:            31Gi        11Gi      594Mi      296Mi        19Gi        19Gi
Swap:          976Mi      970Mi      6.0Mi

Just to re-iterate: I do not think it is a hardware issue, as this file (and others) were able to play a while back.

I created a new container just to be back at default settings (as I played around with transcoding). When I play some of the not working episodes, only the last line of log from my previous post is added, nothing more. No FFmpeg logs, no transcoding popup. The blue circle spins for 30 mins now ...

What I'll try next, are older versions of Jellyfin and copying the files so I can exclude NFS.