from_utc_timestamp()/to_utc_timestamp return incorrect results with EST

hive> SELECT to_utc_timestamp('2016-06-30 06:00:00', 'PST'); 
OK
2016-06-30 13:00:00  ==>Correct, UTC is 7 hours ahead of PST
Time taken: 1.674 seconds, Fetched: 1 row(s)
hive> SELECT to_utc_timestamp('2016-06-30 08:00:00', 'CST');
OK
2016-06-30 13:00:00  ==>Correct, UTC is 5 hours ahead of CST
Time taken: 1.776 seconds, Fetched: 1 row(s)
hive> SELECT to_utc_timestamp('2016-06-30 09:00:00', 'EST');
OK
2016-06-30 14:00:00  ==>Wrong, UTC should be 4 hours ahead of EST
Time taken: 1.686 seconds, Fetched: 1 row(s)
hive> select from_utc_timestamp('2016-06-30 14:00:00', 'EST');
OK
2016-06-30 09:00:00  ==>Wrong, UTC should be 4 hours ahead of EST