one particular virus exe not detected by SEP

Hello,

  In one USB drive, one managed SEP 12.x is not able to detect and quarantine malicious file QJHtQmCmXXcqbsB.exe. However, when I checked the USB drive in another PC (self-managed SEP), it was able to detect and quarantine that particular exe file. All defintions for both SEPs are same (versions also same). Please suggest.