Live session shutdown "hangs" (not showing "Please remove media ..." message)

[Nightfall]

Testing with Kubuntu raring daily iso of 2013-04-18 running as live system from a USB flash drive (on a Samsung R55 laptop).

During shutdown, the system "hangs"; when a key (e.g. Return) gets pressed, shutdown completes.
Probably the "Please remove installation media ..." message (which prompts the user to press Enter to complete shutdown) is missing.

This has been the case with (at least) 2013-04-12's Kubuntu raring daily iso, too.

Could also be a problem with Plymouth/Kubuntu's plymouth theme...
Plymouth splash is the logo one (graphical "Kubuntu" logo with glow is shown).
Version: plymouth-theme-kubuntu-logo: 13.04ubuntu9

This bug might be similar to/the same as bug #966480 (which concerns shutdown after installation).

ProblemType: Bug
DistroRelease: Ubuntu 13.04
Package: casper 1.330
ProcVersionSignature: Ubuntu 3.8.0-18.28-generic 3.8.6
Uname: Linux 3.8.0-18-generic i686
ApportVersion: 2.9.2-0ubuntu8
Architecture: i386
CasperVersion: 1.330
Date: Thu Apr 18 18:34:51 2013
LiveMediaBuild: Kubuntu 13.04 "Raring Ringtail" - Alpha i386 (20130418)
MarkForUpload: True
SourcePackage: casper
UpgradeStatus: No upgrade log present (probably fresh install)

[Nightfall (someoneelse)]

With Kubuntu 12.04 (.0) running from flash drive, the message is displayed during shutdown (same computer; only tried once).

Furthermore, with today's Kubuntu raring daily iso, quickly pressing Esc a few times during shutdown (i.e. switching from splash to message view), the "remove media" message is displayed on the terminal (twice, actually).

[Nightfall (someoneelse)]

Tested different themes using plymouth-x11 (0.8.8-0ubuntu6) on today's Kubuntu raring daily iso:

$ sudo apt-get install plymouth-x11
$ sudo apt-get install plymouth-theme-#...

For all themes:
    $ sudo update-alternatives --config default.plymouth
    # select respective theme
    $ sudo plymouthd && sudo plymouth --show-splash
    # switch to terminal emulator window
    $ sudo plymouth message --text="Please remove installation media and press ENTER:"
    $ sudo plymouth quit

Result (text position on screen in parentheses):

plymouth-theme-edubuntu (13.03.1): no text
plymouth-theme-fade-in (0.8.8-0ubuntu6): ok (top, left)
plymouth-theme-glow (0.8.8-0ubuntu6): ok (top, left)
plymouth-theme-kubuntu-logo (13.04ubuntu11): no text
plymouth-theme-lubuntu-logo (0.38.1): no text
plymouth-theme-sabily (1.2): ok (bottom, center)
plymouth-theme-script (0.8.8-0ubuntu6): ok (top, left)
plymouth-theme-solar (0.8.8-0ubuntu6): ok (top, left)
plymouth-theme-spinfinity (0.8.8-0ubuntu6): ok (top, left)
plymouth-theme-ubuntu-logo (0.8.8-0ubuntu6): no text
plymouth-theme-ubuntustudio-logo (0.46): ok (bottom, center)
plymouth-theme-xubuntu-logo (13.04.4): ok (bottom, center)

If this testing method is correct, the missing message actually might be a plymouth (theme) bug.

During shutdown after testing - having plymouth-theme-xubuntu-logo still selected -, no splash was displayed; after switching to tty1 and back to tty7 it *was* displayed - including the actual/original "Please remove installation media ..." message.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Nightfall (someoneelse)]

Still testing with Kubuntu raring daily iso of 2013-04-19 running as live system:

No message on shutdown on Samsung R55 when "16bit debug override" is enabled in /lib/plymouth/themes/kubuntu-logo/kubuntu-logo.script (uncommented line // Window.GetBitsPerPixel = fun() { return 4; };) (tried once).

No message on shutdown on Samsung NC10 with non-modified theme files (using default kubuntu-logo theme with glowing "Kubuntu" logo being shown) (tried once).