2010 -> 2013 Public Folder migration failed - Property Expression isn't valid

We just migrated from 2003 to 2010, and now on to 2013.  I have Exchange 2013 CU3 installed, and all mailboxes moved.  When trying to move the public folders, I'm getting an error about DataValidationException.  Property expression <PF Name with spaces> isn't valid......

Many articles refer to a mail-enabled public folder with spaces can't have spaces in the alias.  This is NOT a mail-enabled public folder, so there isn't an alias that I can find.

Any ideas?

Thanks!

--Kent