Rhythmbox Last.fm plugin only scrobbles first song when listen to radio

Binary package hint: rhythmbox

I upgraded to Ubuntu 10.04, and now my Last.fm plugin in Rhythmbox will only scrobble the first song when I'm listening to Last.fm radio. Otherwise, it seems to work just fine.

I'm using rhythmbox 0.12.8-0ubuntu6, rhythmbox-plugins 0.12.8-0ubuntu6

To test it, I just listened to the radio station "Artists similar to the stills." I listened to these songs:

Malajube - Jus De Canneberges
Land of Talk - Some Are Lakes
Two Hours Traffic - Territory
The Most Serene Republic - A Mix of Sun and Cloud
French Kicks - The Trial Of The Century

While the first one was playing, I looked at my profile on last.fm, and it said:

Malajube - Jus De Canneberges Listening now

When the song finished, it said:

Malajube - Jus De Canneberges Just listened

But none of the other songs ever showed up, either while I was listening to them or after.

It looks like other people are having the same problems, but as far as I can tell, nobody else has filed a bug report:

http://ubuntuforums.org/showthread.php?t=1477589
http://ubuntuforums.org/showthread.php?t=1417335
http://www.last.fm/group/Rhythmbox/forum/8096/_/595864/2#f12485140

I'm also attaching the output of this command, which I ran to do the above test:
rhythmbox -D audioscrobbler &> rhythmbox-debug2.txt

It looks like for each song, I get these lines:
(11:39:10) [0x9d2040] [rb_audioscrobbler_song_changed_cb] rb-audioscrobbler.c:1146: new entry: <URL>
(11:39:10) [0x9d2040] [rb_audioscrobbler_is_queueable] rb-audioscrobbler.c:484: entry <URL> is queueable

I get that for all songs, even the ones that don't get scrobbled. For the first song, I also get other lines:
(11:39:10) [0x9d2040] [rb_audioscrobbler_timeout_cb] rb-audioscrobbler.c:555: Sending now playing data
(11:39:10) [0x9d2040] [rb_audioscrobbler_perform] rb-audioscrobbler.c:696: Submitting to Audioscrobbler: s=0391c766b5ea4d9492538ed9742a4b14&a=Malajube&t=Jus%20De%20Canneberges&b=Trompe-L'oeil&l=58&n=0&m=
...
(the rest is in the log file)

I ran a similar test previously running this command. It gave different output, so I'm attaching it as well:
rhythmbox -D lastfm &> rhythmbox-debug.txt

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: rhythmbox 0.12.8-0ubuntu6
ProcVersionSignature: Ubuntu 2.6.32-22.36-generic 2.6.32.11+drm33.2
Uname: Linux 2.6.32-22-generic x86_64
NonfreeKernelModules: fglrx
Architecture: amd64
Date: Mon Jun 14 10:38:44 2010
InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release amd64 (20100429)
ProcEnviron:
 LANG=en_US.utf8
 SHELL=/bin/bash
SourcePackage: rhythmbox