Calamares 3.2.17.1 fails to erase existing partition

[ԜаӀtеr Ⅼарсһуnѕkі]

STEPS TO REPRODUCE
 1. Ensure that the target disk has an existing partition on it
 2. Run Calamares
 3. For partitioning, choose to erase the disk

EXPECTED RESULTS
Installation proceeds normally.

ACTUAL RESULTS
Shortly after starting the install, an error dialog is created saying that the "installation failed" and that "the installer failed to create a partition table" with with `sfdisk` command (see attached).

NOTES
 * Fails with BIOS or EFI.
 * Succeeds with other types of partitioning, including manual.
 * Succeeds if the disk does not have an existing partition on it.

WORKAROUND
Delete the partitions before starting the installer.
 OR
Rename/move/delete `os-prober`.

===

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: calamares 3.2.17.1-0ubuntu2
ProcVersionSignature: Ubuntu 5.4.0-12.15-generic 5.4.8
Uname: Linux 5.4.0-12-generic x86_64
.etc.calamares.modules.finished.conf:
 ---
 restartNowMode: user-checked
 restartNowCommand: "systemctl -i reboot"
.etc.calamares.modules.partition.conf:
 efiSystemPartition: "/boot/efi"
 enableLuksAutomatedPartitioning: true
 userSwapChoices: none
 drawNestedPartitions: true
 defaultFileSystemType: "ext4"
.etc.calamares.modules.shellprocess_logs.conf:
 ---
 dontChroot: true
 timeout: 30
 script:
     - calamares-logs-helper @@ROOT@@
.etc.calamares.modules.unpackfs.conf:
 ---
 unpack:
     - source: "/cdrom/casper/filesystem.squashfs"
         sourcefs: "squashfs"
         destination: ""
ApportVersion: 2.20.11-0ubuntu16
Architecture: amd64
CasperVersion: 1.438
CurrentDesktop: LXQt
Date: Thu Jan 30 15:49:42 2020
LiveMediaBuild: Lubuntu 20.04 LTS "Focal Fossa" - Alpha amd64 (20200130)
RelatedPackageVersions:
 calamares-settings-ubuntu-common 1:20.04.1
 calamares-settings-lubuntu 1:20.04.1
 xfsprogs 5.2.1-1ubuntu1
 btrfs-progs 5.2.1-1ubuntu1
SourcePackage: calamares
UpgradeStatus: No upgrade log present (probably fresh install)

[Chris Guiver (guiverc)]

I realize this will be known (Walter), but related I believe to

https://bugs.launchpad.net/ubuntu/+source/calamares/+bug/1851188