F5 is sending very frequent health checks to application servers

Your health check is defined with an 5 seconds interval.

So each cluster member will request each server every 5 seconds (which means 20 times per minutes)

7 hours * 60 minutes * 20 times = 8400

So in a 2 members cluster, each server will receive 16800 requests in 7 hours...

If you want to reduce this number, increase interval...

if you increase interval, the failure detection will be longer.