cdrom scsi passthough not working well

[daggs]

Greetings,

I have a vm running under qemu 5.1.0 with a cdrom scsi passthough into it.
I can eject the device in and out but when I insert a disc, is isn't detected 
and the dmesg on the guest is filled with these prints:
[384216.443262] sr 0:0:0:0: ioctl_internal_command return code = 8000002
[384216.443268] sr 0:0:0:0: Sense Key : 0xb [current]
[384216.443272] sr 0:0:0:0: ASC=0x0 ASCQ=0x6
[384218.504142] sr 0:0:0:0: ioctl_internal_command return code = 8000002
[384218.504150] sr 0:0:0:0: Sense Key : 0xb [current]
[384218.504153] sr 0:0:0:0: ASC=0x0 ASCQ=0x6
[384220.561302] sr 0:0:0:0: ioctl_internal_command return code = 8000002
[384220.561308] sr 0:0:0:0: Sense Key : 0xb [current]
[384220.561312] sr 0:0:0:0: ASC=0x0 ASCQ=0x6

the vm is uefi q35 based, generated by libvirt 6.8.0, the cdrom part is this:
-blockdev 
{"driver":"host_device","filename":"/dev/sg0","node-name":"libvirt-2-backend","read-only":true}
-device 
scsi-generic,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=libvirt-2-backend,id=hostdev0

id there something bad with the config or have I encountered a bug?

Thanks,

Dagg.