Lubuntu 18.04.4 QA-test install; just stops (circling pointer)

Lubuntu 18.04.4 (daily) QA-test install on
dell [optiplex] 755 (c2d-e8300, 8gb, amd/ati radeon rv610/radeon hd2400 pro/xt)

The box hdd (80gb) had 2x prior installs sharing drive; the purpose of install was to replace an existing install with this 18.04.4 image (http://iso.qa.ubuntu.com/qatracker/milestones/384/builds/206417/testcases/1302/results/) with (as most installs these days are 20.04, old system may have had 2x20.04 or 1x18.04,1x20.04)

Using "Something-else"

At "Installation type" I'd selected sda2, clicked "Change" and entered details. I clicked Continue/Okay or whatever box required & was returned to "Installation type" screen which hasn't changed for 60+ minutes; just looping...

(due to length of wait, some details may be fuzzy). I switched to term, could find no squashfs errs or anything else, just loads of "sda: sda1 sda2" lines (journalctl/dmesg)

I'm happy to re-test; the box is primarily used for qa-testing, and Lubuntu 20.04 has been having trouble installing to this box (erase disk & install only) for awhile, but this wasn't an erase & install option.. (https://bugs.launchpad.net/ubuntu/+source/calamares/+bug/1851188))

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubiquity 18.04.14.13
ProcVersionSignature: Ubuntu 5.3.0-28.30~18.04.1-generic 5.3.13
Uname: Linux 5.3.0-28-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.10
Architecture: amd64
CasperVersion: 1.394.1
Date: Tue Jan 21 08:16:10 2020
InstallCmdLine: file=/cdrom/preseed/lubuntu.seed boot=casper only-ubiquity initrd=/casper/initrd quiet splash ---
LiveMediaBuild: Lubuntu 18.04.3 LTS "Bionic Beaver" - Beta amd64 (20200119)
ProcEnviron:
 TERM=linux
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=C.UTF-8
 SHELL=/bin/bash
SourcePackage: ubiquity
UpgradeStatus: No upgrade log present (probably fresh install)