Hi Young,
After checking log, it seem to be the adclient is trying to lookup the user"oracle" which likely to be th reason why you seen the delay. Therefore Could you please help to place user "oracle" under the "/etc/centrifydc/user.ignore" and then run "adreload" to take effect?
Lastly, we do highly recommended to upgrade the DirectControl version to the support version per Robertson advised as the issue could be cause by the enviroment changes in between these version gap.
Thanks.
Andy