Hi @travieso
I was having the same problem yesterday as well.
Like you, I sync with a USB and Local Network connection.
@cgrunenberg kindly came back to me suggesting it could be a server issue, but the problem was persisting this morning.
I deleted the sync location from Settings - Locations section on my iPad and set up the sync again and (so far) it seems to be syncing ok again (it seems slower than before, but so far ok).
Hope this helps.
Rgds SW