Currently, Tajo allows users to set a single global timezone. Since the initial design, the default timezone of a Tajo cluster depends on the JVM timezone if there is no given timezone.
BTW, some of cluster nodes probably can have different timezones due to missed or wrong setting, which actually is usual in practice. It is like to cause wrong results because each task reads and processes a fragment of a single table generated with a single timezone.
In my opinion, the solution is to force Tajo to use an specified timezone instead of depending on JVM timezone. If there is no given timezone, GMT should be used in Tajo cluster.