dba_users - expiry_date - user profile

Oracle DB: RAC  - 11.2.0.4.8

OS: Linux

I am auditing the DBA_USERS tables and found that  column Expiry_Date shows date in past, i.e. 03/27/2014, etc. but the Account_Status = OPEN. How could this be possible?

All these users have the following User_Profile - USERS_GRP1

    

USERNAME -	ACCOUNT_STATUS	EXPIRY_DATE	PROFILE
JPETERS	OPEN	3/27/2014 15:20	USERS_GRP1
BGOLDSMITH	OPEN	5/3/2015 11:29	USERS_GRP1
PLAURY	OPEN	5/9/2012 15:55	USERS_GRP1

CREATE PROFILE USERS_GRP1 LIMIT

  SESSIONS_PER_USER DEFAULT

  CPU_PER_SESSION DEFAULT

  CPU_PER_CALL DEFAULT

  CONNECT_TIME DEFAULT

  IDLE_TIME DEFAULT

  LOGICAL_READS_PER_SESSION DEFAULT

  LOGICAL_READS_PER_CALL DEFAULT

  COMPOSITE_LIMIT DEFAULT