why netapp dfm does send "Clock Skewed" alert from filer?

Issue/Symptom  : DFM sent alert like "Dfm: Error event on Clock Skewed"

■ OS Environment : Netapp ONTAP

■ Investigation : Not performed

■ Workaround Solution :

"options timed.enable off"
"options timed.enable on"

■ Permanent Solution :

• Unknown.

■ Root Cause Analysis :

unknown