Fortigate Firewall Policy stuck with 0 Bytes

hi,

i have a FW policy whose 'bytes' column stuck with 0 and it's not incrementing.

i can see FW policy matching log and fortiview session traffic.

i created a clone of the FW policy earlier for troubleshooting, place above the original FW policy, allowed any source and destination address, deleted the cloned FW policy after i saw traffic matched, then revert back original FW policy to specific source/destination subnet.

i tried to update statistics and clear counters but to no avail.

is there any other troubleshooting step i can do in order for the FW policy to display increment in the 'bytes' column?