Deferrals Not Resumed after a Leave of Absence

A  participant was deferring prior to a leave of absence without pay.  Participant  was on leave from April 1 to June 30th.  Employer forgot to resume participant's deferrals after participant returned to the company.  Is the corrective deferral from July 1 through December 31 based on the participant's original deferral election or  50% of the participant's deferral election.