Date [node:field-name-here:custom:?] tokens are not displaying correctly when used for automatic node titles. The titles using "Date tokens" are displayed -1 year from whatever date you selected on the node. So if you select 2011 in the node, and then save. You will see the token generated 2010 for the node title.
1. Create a new content type.
2. Add a date field to that content type. (Year, field_year, Date, Select List)
3. Configure automatic title generation for that content type. Check "Automatically generate the title and hide the title field". Use [node:field-year:custom:Y] as your "Pattern for the title".
4. Create a node for that content type. Select a "Year" value and save.
5. The date thats specified in the node is -1 year for the title. So if you selected 2011 it would show 2010 instead.