Comment 7 for bug 1750465

Some thoughts here:
 - bash is shown as being unpacked immediately before this. bash is an essential package.
 - the package which triggers the plymouth theme packages is base-files, which ships /etc/lsb-release. base-files is also an essential package.
 - apt tries to handle Essential packages specially, by configuring them as quickly as possible.
 - the plymouth packages use 'interest' triggers, not 'interest-noawait' triggers, so the base-files package can't be configured until after the plymouth triggers have been run.
 - dpkg doesn't let the triggers be run before the dependencies are configured.

I think it's very likely that this is a package manager bug, since I don't see any dependency loops anywhere involving lsb-release and plymouth-themes-ubuntu-text. However, we can probably also work around it by making the plymouth triggers use interest-noawait instead, so that they do not block the configuration of essential packages.

I also think this warrants an SRU, since the version of the theme package being triggered may be the old version during a release upgrade.