Now some progress - and a workaround:
It would seem that LibreOffice is having trouble with correctly retrieving other label formats, than the “native” label format, from the printer (printer driver). The default label format for this printer is 103mm x 164mm. When selecting this format, LibreOffice will preview (and print) correctly - even though the loaded media is more like 101.6mm x 164mm
Selecting this media (103 mm while the media is actually 101.6mm) prevents all other applications from printing - so the workaround for me - is to switch printer configuration before printing with LibreOffice - and switching back when printing with LibreOffice has completed.
Luckily for me - printing with LibreOffice is done using PowerShell in my case, so the script just needed to alter printer configuration.
Before printing:
$Hex = @"
42,00,72,00,6f,00,74,00,68,00,65,00,72,00,20,00,51,00,\
4c,00,2d,00,31,00,31,00,31,00,30,00,4e,00,57,00,42,00,00,00,00,00,00,00,00,\
00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,01,04,00,05,\
dc,00,52,01,0f,65,01,00,02,00,81,01,6b,06,f8,03,64,00,01,00,00,00,2c,01,01,\
00,01,00,2c,01,03,00,00,00,31,00,30,00,33,00,6d,00,6d,00,20,00,78,00,20,00,\
31,00,36,00,34,00,6d,00,6d,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,\
00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,\
00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,\
00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,\
00,00,1e,00,00,00,ef,00,81,01,00,00,3b,00,01,00,00,00,1e,00,95,07,00,00,01,\
00,00,00,42,52,50,54,00,00,00,00,00,00,00,00,6b,81,04,00,07,e5,0b,00,50,52,\
49,56,a0,30,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,\
00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,\
00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,\
00,00,00,00,00,00,00,00,00,00,00,18,00,00,00,00,00,10,27,10,27,10,27,00,00,\
10,27,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,\
00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,\
00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,\
00,0d,00,18,00,00,00,00,00,03,00,00,95,07,00,00,6b,06,00,00,6b,06,00,00,30,\
75,00,00,fe,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,01,00,00,01,3b,00,\
00,00,00,00,01,00,01,01,01,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,\
00,00,00,00,00,6b,81,04,00,07,e5,0b,00,00,00,00,00,00,00,12,01,00,0f,01,00,\
00,00,00,00,00,00,00,00,00,00,00,00,00,00,00
"@
$Data = [byte[]]$($($Hex -replace "\\|\s",'').Split(',') | % { "0x$_"})
New-ItemProperty -Path HKCU:Printers\DevModes2 -Name "Brother QL-1110NWB" -PropertyType Binary -Value $Data -Force | Out-Null
New-ItemProperty -Path HKCU:Printers\DevModePerUser -Name "Brother QL-1110NWB" -PropertyType Binary -Value $Data -Force | Out-Null
After printing, the configuration is switched back, to what I would call “the correct configuration”:
$Hex = @"
42,00,72,00,6f,00,74,00,68,00,65,00,72,00,20,00,51,00,\
4c,00,2d,00,31,00,31,00,31,00,30,00,4e,00,57,00,42,00,00,00,00,00,00,00,00,\
00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,01,04,00,05,\
dc,00,52,01,0f,65,01,00,02,00,4d,01,68,06,e6,00,64,00,01,00,00,00,2c,01,01,\
00,01,00,2c,01,03,00,00,00,4a,00,65,00,6e,00,54,00,72,00,6f,00,6e,00,69,00,\
63,00,00,00,6d,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,\
00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,\
00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,\
00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,\
00,00,1e,00,00,00,ef,00,04,01,00,00,23,00,01,00,00,00,1e,00,91,07,00,00,01,\
00,00,00,42,52,50,54,00,00,00,00,00,00,00,00,6b,81,04,00,07,e5,0b,00,50,52,\
49,56,a0,30,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,\
00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,\
00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,\
00,00,00,00,00,00,00,00,00,00,00,18,00,00,00,00,00,10,27,10,27,10,27,00,00,\
10,27,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,\
00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,\
00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,\
00,18,00,02,00,11,00,00,00,03,00,00,91,07,00,00,68,06,00,00,68,06,00,00,30,\
75,00,00,fe,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,01,00,00,01,23,00,\
00,00,00,00,01,00,01,01,01,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,\
00,00,00,00,00,6b,81,04,00,07,e5,0b,00,00,00,00,00,00,00,12,01,00,0f,01,00,\
00,00,00,00,00,00,00,00,00,00,00,00,00,00,00
"@
$Data = [byte[]]$($($Hex -replace "\\|\s",'').Split(',') | % { "0x$_"})
New-ItemProperty -Path HKCU:Printers\DevModes2 -Name "Brother QL-1110NWB" -PropertyType Binary -Value $Data -Force | Out-Null
New-ItemProperty -Path HKCU:Printers\DevModePerUser -Name "Brother QL-1110NWB" -PropertyType Binary -Value $Data -Force | Out-Null