Several weeks ago, myITforum.com started a "known issues" list for the System Center 2012 R2 releases. The list provides helpful guidance for those beating their heads against the wall due to surprising problems in the new release. Lists like these are extremely valuable as they provide IT Pros the ability to know when there is a problem with a product, allowing them to minimize troubleshooting since the issues aren't due to their own infrastructure or specific implementation.
In the ConfigMgr 2012 R2 known issues list, there's a stated issue with the task sequences and the inability for ConfigMgr 2012 R2 to read computer variables.
A Hotfix for this issue is now available.
Per-computer task sequence variables that are defined for imported computers are filtered out of client policies. This prevents the variables from being read during task sequence execution. This problem does not affect per-computer variables that are defined for existing clients.