session clash log

hi, 

Please tell me why the log occurred and how to take action.

I am using forti-OS 5.6.8

07 | 20 | "0100020085" | session clash" new_status="state=00010404 tuple-num=2 policyid=107 identidx=0 dir=0 act=2 hook=0 1.226.64.90:43443->172.25.5.234:5911(218.146.32.6:10329)

dir=1 act=1 hook=4 218.146.32.6:10329->1.226.64.90:43443(172.25.5.234:5911)" old_status="state=00010404 tuple-num=2 policyid=107 identidx=0 dir=0 act=2 hook=0

1.226.64.90:43443->172.25.5.234:5909(218.146.32.6:10329) dir=1 act=1 hook=4 218.146.32.6:10329->1.226.64.90:43443(172.25.5.234:5909)

thanks