Question was also posted to the helpdesk, ticket 13119, repeating answer here for everyone else.
- Delete the first line of the shading csv file "This file contains external shading fractions for all shading surfaces of all zones."
- The shading schedule file must contain a full year of data, even if you do not intend to run all months.
The schedule file reader does not read the date/time stamps in column 1, it simply assumes that the first row of data is 01/01 hour 1, and so on.
See related open issue #6482.