Fortigate Forward Traffic Log not showing Policy ID Number (x)

Have you tried upgrading the firmware. This can be a known issue on the firmware. Also it is recommended to go to the latest version of the FGT. 
what is the FGT model ?

What if you select the log and click on details? ID number is showing there?

Seems like it is a bug. To be more sure you can try to upgrade it to 7.4.0, otherwise you can create a support ticket for bug identification.

I will also try to reproduce it in my LAB. I will keep you posted.

Also if possible, share here a row log entry in txt format.

Hi @dgullett 

Check Logging Settings: Make sure that the logging settings for your policies are configured to include the Policy ID in the logs. To do this:

• Log in to your FortiGate firewall's web interface.
• Navigate to "Policy & Objects" > "IPv4 Policy" (or "IPv6 Policy" if applicable).
• Select the policy for which you want to see the Policy ID in the logs.
• In the "Logging Options" section, ensure that "Log Allowed Traffic" or "Log Denied Traffic" is selected, and that the "Policy ID" checkbox is checked.

Thanks,

Kruthi