Going back to change the installer's language doesn't update the default keyboard layout

I'm testing the groovy daily ISO, and while running through http://iso.qa.ubuntu.com/qatracker/testcases/1469/info I noticed this minor bug:

 * In the installer's first page, select your language of choice, then click "Install Ubuntu"
 * Verify that the keyboard layout selected by default matches your language
 * Click the back button and select a different language, then click "Continue"

Expected result: the keyboard layout selected by default has changed to match your new language selection

Actual result: the selected keyboard layout remains the same.

ProblemType: Bug
DistroRelease: Ubuntu 20.10
Package: ubiquity 20.10.10
ProcVersionSignature: Ubuntu 5.8.0-22.23-generic 5.8.14
Uname: Linux 5.8.0-22-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu49
Architecture: amd64
CasperMD5CheckResult: pass
CasperVersion: 1.452
CurrentDesktop: ubuntu:GNOME
Date: Tue Oct 13 11:05:24 2020
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz file=/cdrom/preseed/ubuntu.seed maybe-ubiquity quiet splash ---
LiveMediaBuild: Ubuntu 20.10 "Groovy Gorilla" - Beta amd64 (20201013.1)
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=es_ES.UTF-8
 SHELL=/bin/bash
SourcePackage: ubiquity
UpgradeStatus: No upgrade log present (probably fresh install)