It seems as though the “=>” character in a note title broke Obsidian Sync for Android. The sync log showed a FILE_NOTCREATED error and then no further output, despite there being many more notes still to sync.
I’m seeing that there are a bunch of characters that I can put in note titles on Obsidian for Mac without getting a warning, but which trigger a FILE_NOTCREATED error on Android. Another example is double quotation mark (").