The credentials provided for the Oracle source are invalid

I just received my first report from a user of a similar problem with a SQL Server data source. I tested and confirmed the behavior is consistent with other reports here (i.e. manual refresh works in Desktop, the Data Source connection tests sucessfully, but the scheduled refresh fails with a credentials error).

I'm having everyone check to make sure they turn that preview feature off in Desktop. Why on earth Microsoft would default an optional feature like that to "on" is beyond me. Hopefully the user in question can find a backup copy that wasn't converted to the new format.