I pushed up a change to fix the timestamp issue (I fixed it for the 'datetime' type, but liquibase manages 'timestamp' separately). The fix should also use getdate() instead of now().
I published a new 1.0 snapshot release at https://github.com/liquibase/liquibase-redshift/releases/tag/snapshot-4 with the fixes.
Let me know how it works and if it seems ready for the official 1.0 release since I don't have an actual redshift database to test against.
Nathan