monitor timeouts vs actual behaviour

Chris, I've just checked my 10.2.4 big-ip and did a tcpdump on a pool member with a http monitor (as you've got in the example above). The connections are exactly 5secs apart on mine and I was able to mark the pool member down after 16secs and then back up again on a single poll (less than 5secs). Unless I've missed anything else to recreate your testing then it seems to be working as it should. Sorry I haven't got an answer for you but wanted to reassure you that it should work as documented. Have you got any other traffic muddying the water? N