Update Manager did not perform requested action for user modified GRUB file

After installing Precise Pangolin I changed /etc/default/grub by uncommenting "GRUB_TERMINAL=console" so that I could see the boot menu. I dual boot Windows XP and without this change, no menu is displayed (Precise comes up after menu time out). This week's updates had a new version of this file so, when prompted, I requested a side by side comparison of the files, fully intending to install the new version and go back and make this change as necessary. Instead, no comparison was shown and the existing file was left untouched. The request should have been honored and either followed with another prompt for installing the file or automatically making the new file available somewhere.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: update-manager 1:0.156.14.5
ProcVersionSignature: Ubuntu 3.2.0-24.39-generic-pae 3.2.16
Uname: Linux 3.2.0-24-generic-pae i686
ApportVersion: 2.0.1-0ubuntu8
Architecture: i386
Date: Mon Jun 4 14:03:51 2012
GsettingsChanges:
 com.ubuntu.update-manager first-run false
 com.ubuntu.update-manager launch-time 1338818790
 com.ubuntu.update-manager window-height 500
 com.ubuntu.update-manager window-width 600
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release i386 (20120423)
PackageArchitecture: all
ProcEnviron:
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: update-manager
UpgradeStatus: No upgrade log present (probably fresh install)