Application Crash

Dears Our forti was unavailable for 1 hour and we did not have incomming traffice. After checking forti logs, we get following. Did wad cause this issue.? Nov 8 14:12:03 2021-11-08T14:12:01+03:30 - - - - <188>date=2021-11-08,time=14:12:03,devname="fg1000D-FW-01-RS6",devid="FGT1KD3915801869",logid="0100032546",type="event",subtype="system",level="warning",vd="root",eventtime=1636368123108269181,tz="+0330",logdesc="Application crashed",action="crash",msg="Pid: 05415, application: wad, Firmware: FortiGate-1000D v6.4.2,build1723b1723,200730 (GA) (Release), Signal 11 received, Backtrace: [0x01fb6ce5] [0x01fb7df0] [0x01fb81c8] [0x01fa4bee] [0x016b603e] [0x016c2a1c] [0x0166d83a] [0x016d5e84] [0x00435448] [0x0043c0c4] [0x7fd0ae3c2eaa] [0x00431daa