After further investigation, this appears to be upstream bug https://bugs.freedesktop.org/show_bug.cgi?id=80553, which was fixed in http://cgit.freedesktop.org/plymouth/commit/?id=84eb4381db85877a9a56b35994e6 c10d43e46ebe, which in turn is part of upstream Plymouth 0.9.2.
I have confirmed that "apt-get source plymouth" and rebuilding the packages from upstream 0.9.2 resolves this issue for me. I don't really want to try uploading this as a package update myself, as I haven't done this before so I've probably done something wrong, but if the official maintainer is interested in my updated sources just let me know where to send them. (I did have to adjust a few of the patches to get it to build -- also the plymouth-x11 package seems to be very lonely now as it only contains one .so; the log viewer that used to be in there appears to no longer exist.) -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org