No duplex printing

[John Rose]

On Ubuntu Focal desktop 64 bit, neither Samsung SCX-472FD monochrome laser printer nor HP M254dw colour laser printer prints duplex. Was OK on Ubuntu Bionic until upgrade to Focal.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: cups 2.3.1-9ubuntu1.1
ProcVersionSignature: Ubuntu 5.4.0-48.52-generic 5.4.60
Uname: Linux 5.4.0-48-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.9
Architecture: amd64
CasperMD5CheckResult: skip
CupsErrorLog:

CurrentDesktop: ubuntu:GNOME
Date: Fri Oct 2 12:06:08 2020
InstallationDate: Installed on 2019-02-12 (597 days ago)
InstallationMedia: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725)
Lpstat:
 device for HP-ColorLaserJet-M254dw: dnssd://HP%20Color%20LaserJet%20M254dw%20(AE5DF9)._ipp._tcp.local/?uuid=564e4335-5434-3330-3836-80e82cae5df9
 device for Samsung-SCX-472x: socket://192.168.101.30:9100
Papersize: letter
PpdFiles:
 Error: command ['fgrep', '-H', '*NickName', '/etc/cups/ppd/Samsung-SCX-472x.ppd', '/etc/cups/ppd/HP-ColorLaserJet-M254dw.ppd'] failed with exit code 2: grep: /etc/cups/ppd/Samsung-SCX-472x.ppd: Permission denied
 grep: /etc/cups/ppd/HP-ColorLaserJet-M254dw.ppd: Permission denied
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.4.0-48-generic root=UUID=55db4860-53d3-4294-aa82-f5d21d00f11c ro quiet splash vt.handoff=7
SourcePackage: cups
UpgradeStatus: Upgraded to focal on 2020-09-29 (2 days ago)
dmi.bios.date: 03/14/2018
dmi.bios.vendor: Intel Corp.
dmi.bios.version: PYBSWCEL.86A.0069.2018.0314.1745
dmi.board.name: NUC5CPYB
dmi.board.vendor: Intel Corporation
dmi.board.version: H61145-404
dmi.chassis.type: 3
dmi.modalias: dmi:bvnIntelCorp.:bvrPYBSWCEL.86A.0069.2018.0314.1745:bd03/14/2018:svn:pn:pvr:rvnIntelCorporation:rnNUC5CPYB:rvrH61145-404:cvn:ct3:cvr: