[Zubersoft]

It definitely sounds like the custom stamp is throwing off the sync. If you've used that custom stamp in one of your songs but the custom stamp is missing from the device, I would advise deleting that stamp and then trying the sync again. If you need help with this, go to C:\Users\<your username>\AppData\Local\Packages\41730Zubersoft.MobileSheets_ys1c8ct2g6ypr\LocalState, email mobilesheets.db to mike@zubersoft.com and I can either fix the database or tell you which song(s) need to be fixed. It sounds like I may need to do some additional testing where I have references to custom stamps, delete those files and then try to sync. 

Mike