My guess is you are improperly using the object Any in the Destination or Service of your HTTPS Inspection policy and it is pulling all traffic into F2F for active streaming. Use object Internet for the Destination (you will also need to make sure your firewall topology is completely and correctly defined to ensure this object is being calculated correctly) and only use explicit services like https in your HTTPS Inspection policy. You might have an "Any Any Any" cleanup rule at the end of your HTTPS Inspection policy, big no-no.
Another possibility is that all traffic is fragmented due to an incorrect MTU somewhere. Please provide the output of fw ctl pstat.
Last possibility is that you are using ISP Redundancy in Load Sharing Mode, Cluster Load Sharing with Sticky Decision Function enabled, or are using your firewall as an explicit HTTP/HTTPS web proxy, pretty much everything will go F2F as a result in any of those cases.
If practically all the traffic passing through this firewall is outbound user traffic to the Internet and subject to HTTPS Inspection, the 98% F2F might be legit.
Don't worry about templating rates, totally separate issue that is not the problem.
Could also be something in your TP policy causing the high F2F, we'll deal with that once you check your HTTPS Inspection Policy, fragmentation, and the three features I mentioned.
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