Thanks for posting this fresh take on Lightroom Mobile's longstanding sync issues. As I'm sure you saw if you did any sort of search related to the issue here, there are hundreds of posts about it, going back many months. It sure would be nice if Adobe could fix this once and for all!
The common suggestion to resolve the issue is to remove the sync.lrdata file, but are we seriously expected to do that every other day? That's what it would take, as I'm finding that it gets stuck again within a few hours, every time I do anything that manages to kickstart the sync process. I'm about ready to give up on syncing altogether, quite honestly.
I would also like to hear what folks suggest for getting RAW files, taken in Lightroom Mobile via iOS 10 and a recent iPhone, off the phone and into Lightroom without having to struggle with the above mentioned challenges of the sync process.