Sansa Clip Zip is changing my playlists (zapping external memory references)

I’ve read several posts on playlist issues, but I haven’t seen an issue like this.

I’ve created Playlists in my new Clip Zip from songs in my internal memory and my external microsdhc card. I did this via Windows Explorer by creating a new playlist in the internal playlist folder, and dragged and dropped them to the new playlist (it is .pla format).  I was then able to disconnect from my computer, and was successful in playing the playlist, accessing songs from both internal memory and the external card.  I even powered the Clip Zip down and turned it back on to ensure persistance (and it still worked). 

Upon reconnection to my computer, the Clip Zip somehow modified the playlist and deleted ALL entries from the external card.   I tried again, with the same results (edited the playlist, disconnected, worked successfully, reconnected, Clip Zip zapped the entries). 

So I did it again, this time creating copies of the playlist in the playlist AND root folders of the internal memory.  Tested again with the same results.

For some reason, when I connect with the USB, it will Zap all references to external memory songs in all .pla files in internal memory.  What am I doing wrong???  Could it be a problem with the new firmware update (I heard that is problematic), and if so, how do I back it out?  Or is there some setting where I can tell Clip Zip “Do as I SAY, not as you THINK”? 

Thanks in advance.