history command displays incorrect execution command time

Issue

When history internal bash command is run, it displays incorrect timestamp with some entries:

$ history
    1  14/10/15 09:35:43 who
    2  14/10/15 09:35:43 ps
    3  14/10/15 09:35:43 set
    4  14/10/15 09:35:43 exit
    5  14/10/15 09:35:43 pam_tally2 -u ocru
    6  14/10/15 09:35:43 passwd ocru
    7  14/10/15 09:35:43 su - ocru
    8  14/10/15 09:35:43 exit
    9  11/09/15 16:07:25 cd /data
   10  11/09/15 16:07:27 ls -ltrh
   11  11/09/15 16:08:02 ps
   12  11/09/15 16:08:04 top
   13  11/09/15 16:08:52 cd
   14  11/09/15 16:09:01 ls
   15  11/09/15 16:12:15 exit
   16  14/10/15 09:35:44 history