unknown icmp log

I found one of my vdom have many traffic log with the service 3/3/icmp allowed. I only permitted DNS traffic in my policy and icmp should be blocked. Also, I did not enable " log allowed traffic" , so it makes me don' t understand why I would got such traffic log on my fortigate. Can anyone tell us what are those log and why it appears on the traffic log? Below is the one of the raw log as I said: log_id=5 type=traffic subtype=other pri=notice vd=*** status=" accept" dir_disp=" org" tran_disp=" noop" src=" 10.***.***.***" srcname=" 10.***.***.***" src_port=0 dst=" 10.***.***.***" dstname=" 10.***.***.***" dst_country=" Reserved" dst_port=771 tran_ip=" N/A" tran_port=0 tran_sip=" N/A" tran_sport=0 service=" 3/3/icmp" proto=1 app_type=" N/A" duration=0 rule=18 policyid=18 identidx=0 sent=0 rcvd=0 shaper_drop_sent=0 shaper_drop_rcvd=0 perip_drop=0 shaper_sent_name=" n/a" shaper_rcvd_name=" n/a" perip_name=" n/a" sent_pkt=0 rcvd_pkt=0 vpn=" n/a" vpn_type=" n/a" vpn_tunnel=" n/a" src_int=" WC-Trust" dst_int=" WC-UnTrust" SN=********** app=" N/A" app_cat=" N/A" user=" n/a" group=" n/a" carrier_ep=" N/A" profilegroup=" N/A"