No "minimum partition size" warning before install !

[pg Scorpio]

Installer does NOT tell the minimum size for partitions during install.
Installer always suggests minimum space for partitions 10GB, but this makes no sense !
Installer does accept partition sizes when pressing install, but fails on "Insufficient space" !

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: ubiquity 20.04.15.2
ProcVersionSignature: Ubuntu 5.4.0-53.59-lowlatency 5.4.65
Uname: Linux 5.4.0-53-lowlatency x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu27.12
Architecture: amd64
CasperVersion: 1.445.1
Date: Fri Nov 27 23:19:44 2020
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz boot=casper file=/cdrom/preseed/ubuntustudio.seed fsck.mode=skip quiet splash ---
LiveMediaBuild: JamulusOS v2.00-EN amd64 "Custom Focal Fossa" (20201113)
SourcePackage: ubiquity
UpgradeStatus: No upgrade log present (probably fresh install)