This bug has been opened here: http://bugzilla.ubuntu.com/show_bug.cgi?id=21850

"(gst 0.10 RH)

The seek bar doesn't work very well/smoothly. 
Quite often (say at least once in 20 manipulations), when I move the seek bar
with the mouse, it will exbihit some kind of glitch, during a split a second.
Hard to describe... for example, say the button is in the middle, and I move it
to the right. Well, sometimes, the button will decide to "jump" to the far left,
or far right, or anywhere, then eventually come back where I meant to move it to.
Sometimes, it doesn't even want to go where I want it to, and the cursor/button
(don't know how to call it...) ends up an inch backwards.
Also, when it does this, often, it will stay mute for like 2 seconds, before
resuming the playback.

I first noticed this problem when playing back a podcast episode, and since they
are mp3 files, I thought maybe it's a bug the "ugly" plug-in. So I tried with
OGG songs, and the problem is there as well. Also, I tried both MP3 and OGG with
Totem-gst0.10, and couldn't reproduce the problem neither with OGG or MP3. So it
really seems to be a RH specific problem..."