Same problem, here's how I solved it. With my iPad connected to my computer, I did the following in iTunes:
•I selected (My)iPad under Devices and clicked on the Summary tab at the top.
•Under "Options" I unchecked "Convert higher bit rate songs to 128 kpbs AAC".
•Then I went to (My)iPad>Music in the left column and clicked on the Autofill button at the bottom right of the iTunes window.
•A window opened asking if I wanted the iPad songs replaced with (the same) songs from this iTunes library, and I clicked "Replace Songs".
•When it finished recopying the songs onto my iPad, the songs played normally --but my Playlists were missing from the iPad.
•So, in the iTunes left column I dragged the missing playlists up to my iPad list.
•Finally I hit the Sync button to send the playlists to my iPad. then clicked Apply.
After days of frustration all seems normal now!