ubiquity incorrectly reports computer name "already exists on the network" until text in other fields is changed

When installing with ubiquity 2.7.14 on the Oneiric i386 20110817 daily-live, for any computer name I manually specify, the installer shows the green check mark for a short time (less than a second), but then always says "That name already exists on the network." This happens even for names that certainly do not exist on the network. This has been happening for quite some time--I think for all Oneiric alphas and daily-lives, and as detailed below, this bug probably exists in Natty as well. For the purposes of reporting this bug, I have used the output of uuidgen as my computer name (4a15ead9-c343-4fa6-bfa8-ad18ae3c6a89). However, this does not only occur with long computer names and computer names that contain dashes--it also occurs with more common computer names, like Nyaa (which does not currently exist on my network) and Tweed (which has never existed on my network). I have tried numerous other names as well, and they all produce the message.

This may be the same as the condition reported in bug 760884. I am reporting a new bug because, in effect, that bug documents the old (fixed) problem that a duplicate computer name during installation was an error (preventing installation) rather than a warning. Bug 760884 was marked Fix Released when that problem was fixed, and the bug I am reporting here never prevents installation from proceeding.

However, there are also three possible differences between the situation described here and the situation described originally in bug 760884:

(1) Pjotr12345 reported that a "random name with a dot in it" was accepted. I have found that names containing a single . character produce the warning message, same as names without a dot.

(2) Rather than manually specifying a name appearing to cause the warning, it appears instead that the warning is shown except when the text in any of the other fields is changed. Changing the username--even if I immediately change it back to what it was--causes the warning message about the computer name to go away, as does changing the user's full name or password. Changing the computer name--even if it is immediately changed back to what it was--causes the message to come back (and then it can be dismissed again by changing the username). Automatically generated computer names are generated from the first user's username (like ek-virtual-machine), so automatically generated names may not be a special case. I suspect that this is the original behavior from bug 738732 and bug 760884, but perhaps this is new with Oneiric.

(3) The green check mark appears initially when a new computer name is entered, but then gives way to the warning message in a fraction of a second. It is unclear to me from previous reports if this is new behavior.

For convenience, the attached screenshot illustrates the warning message.

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: ubiquity 2.7.14
ProcVersionSignature: Ubuntu 3.0.0-8.11-generic 3.0.1
Uname: Linux 3.0.0-8-generic i686
Architecture: i386
CasperVersion: 1.278
Date: Wed Aug 17 12:31:16 2011
ExecutablePath: /usr/lib/ubiquity/bin/ubiquity
InterpreterPath: /usr/bin/python2.7
LiveMediaBuild: Ubuntu 11.10 "Oneiric Ocelot" - Alpha i386 (20110817)
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: ubiquity
UpgradeStatus: No upgrade log present (probably fresh install)