Why do modification time stamp of a file showing few mintues ahead of system time ?

Issue

• When checking the lasting modification time of a file, showing that the file had been modified few minutes ahead of system time.

[root@server]# ls -ltr 
-rw-r--r--  1 user user  1480735 Jan 16  2015 xyz.log.2015-01-16-08
-rw-r--r--  1 user user  1210747 Jan 16  2015 abc.log
[root@server]# date
Fri Jan 16 09:20:08 CST 2015
[root@server]# date -r ./abc.log
Fri Jan 16 09:47:07 CST 2015
The file modification time is 27 mintues ahead of system time.