Issues after upgrading to 23.4R1

• Considerable in flux of RT_FLOW logs.
• Upgraded to 23.4R1 or later.

This is caused to Drop-Flow, which in order to save resources instead of just dropping packets in a denied flow, creates a drop flow session.

https://www.juniper.net/documentation/us/en/software/junos/release-notes/23.4/junos-release-notes-23.4r1/topics/new-features/feature-descriptions/flow-based-packet-based-processing-9.html

As a workaround, you may disable drop-flow with: "set security flow drop-flow max-sessions 0".