iOS synchronization issues

I've just installed Joplin desktop 1.2.6 and imported some notebooks from EverNote. Everything is working well on the desktop version (though synch with DropBox is slow).
However, on Joplin mobile for iOS 10.2.1, I keep getting synch issues
error invalid parameters in updateSyncTimeQueires
Sometimes I can fix this by removing extended ASCII characters (like 171 for ½)
but sometimes I cannot figure out why it's bombing.

Anyone? I've posted this a bug on GitHub ( with requested sample file, but no response.