Traffic hitting policy name "pre-id-default-policy-logical-system-00/3" when no policy is configured with that name.
Session ID: 20, Policy name: pre-id-default-policy-logical-system-00, HA State: Active, Timeout: 1798, Session State: Valid
That policy match comes from this line of configuration:
set security policies pre-id-default-policy then log session-init
We generally don't suggest enabling this particular piece of configuration unless you're troubleshooting issues with session setup.
We do recommend to keep the 'session-close' piece of configuration (which is present by default in current releases) as it will notify you if flows are being closed prior to being identified by JDPI. This can sometimes be indicative of evasive behavior and should be investigated.
set security policies pre-id-default-policy then log session-close
In case you're not aware, all flows that match unified-policies are assigned to the pre-id-default-policy (after basic 5-tuple matching) while JDPI inspects the flow and classifies the layer-7 application. This will generally take a few packets at minimum to have the first classification event, so it's normal to see flows sitting in pre-id-default-policy that have only passed a few packets through the SRX.