Having ZUNE Shuffle Issues?

Okay, so this has nothing to do with federated infrastructure, except that many of my customers have or are considering Zunes.  I have one and I have what I believe to be a common problem.  My music collection contains some content that may be inappropriate for children under the age of 30.  I also like to shuffle the music around.  It seems the easiest way to accomplish this is to create a playlist of all age-appropriate music and then shuffle that playlist.  So I create a playlist with probably 2,400 songs or so.  The playlist syncs to the Zune device, and then immediately disappears.  Never shows up again.

I split the playlist into two smaller ones, each of about 1,200 songs.  Now I can listen to half my collection, but every couple of days need to switch over to the other half.  So, I've been listening to my collection for about a month now and notice that is seems like a pretty tight rotation.  If I wanted that, I would just turn on the radio.  I also notice that several of the songs on my collection are not getting played at all.  So I begin doing some tests.

These are my results, but I would like to know if anyone else is seeing something similar.  The shuffle feature in the Zune does not appear to be random.  I've noticed it always plays the same subset of songs in the same order.  I verified this by writing down the first 10 songs in a "random shuffle."  I stopped the Zune, started it over, and got the same 10 songs again. 

My work-around has been to shuffle the playlist in the list editor and just play them sequentially.  The past couple of weeks have been great; I am hearing songs that I know have never played before on the Zune.  Anyone else notice this?