Strange timestamp of Dialup Session

Dear Experts,

In FortiVew > Summary View > SSL&Dialup IPsec, 

I can see SSLVPN users and IPsec branch offices successfully connecting to our Fortigate-100D. 

But strangely, all the Connection Time of Dialup Session are same.

"01/01 09:00 - 01/01 09:00"

In Fortianalyzer, other time and date of logs like "Top source" "System Events" are  working correctly.

I also checked VPN logs in Fortigate, and found that those time are correct. 

How can I fix this?  Any ideas?

- Fortianalyzer-200D with 5.2.1(latest)

Thanks in advance