[Zubersoft]

If you use the library sync feature, you have control over whether it is a two-way sync or one-way, and you also control what type of information is merged, such as annotations. If you merged everything, performed a two-way merge, and set the merge behavior to "Use song that was modified last", then it's possible the song on the phone had a newer last modified timestamp and it was used to replace the song on the tablet. If the song on the phone didn't have annotations it could replace the song on the tablet and clear the annotations. Is it possible that is what happened? Or were the libraries pretty much identical before the sync?

Thanks,
Mike