OK folks, here is the update. Yes, re-encoding solved the problem for some problematic songs. However, they are shown as Unknown Album, and Unknown Artist, since I converted them to WAV first. I encoded them to AAC later. So, if I edit the tag information, will it sync multiple copies again?
On the other hand, since I added new songs to my library, the software starting to resync those over and over again.
It looks like everytime I add a couple of songs, it will repeat this mistake. They have fine tags, I edited them in the mp3tag software using UTF-ISO prior to adding them to the library! I am really hoping that the December update will address this issue. This is really getting annoying and renders the player pretty much unusable. What the heck were they "syncing" about prior to releasing this software which seems to be full of bugs!
There is a playlist problem. I do not know if it's related to syncing, so I just post here. Since there are some differences between the playlists on the software and those on the device (in terms of number of songs and arrangement of those), I wanted to delete one of those playlists on the software and then recreate. However, after I delete the playlist, it does not let me create with the same name because it says it already exists. But, it's not showing up there. I went to the Zune folder under My Music, the playlist I wanted to recreate is still there even though I deleted in the software which causes to give the warning message that it exists. There seems to be a lack of communication between the software and the playlists folder under Zune folder. Also, there are playlists in this folder that do not show up under the software. Prior to installation, I deleted all the previous Zune folder under My Music. Do you know what causes this and how I solve this problem? I know God and hopefully Zune team does =).