I'm still having issues unfortunately.
Not working completely for me, either.
I've re-opened the GitHub issue and have proposed a change to the original workaround.
Locally, I haven't experienced the "Lock has expired" error, but am currently testing the updated workaround by syncing roughly 2000 notes (I may experience the lock error during this sync).
Thank you for the additional information.
See also:
- A workaround for an older sync-lock-related issue (may be helpful as a temporary workaround for the "sync lock" issue)
- GitHub issue for the iOS/Android Dropbox sync issue
- Upstream Dropbox forum discussion
- GitHub issue that proposes removing sync locks