FQDN Node Configuration

First, when using an FQDN you do not have any need to create the node manually or any pool member for that matter because the F5 will automatically create the appropriate node if it doesn't exist. Second, make sure that you modify the FQDN TTL value otherwise the F5 will not honor the TTL provided by the DNS server in question. Third, the F5 will always perform health monitors from the IP with the more specific route. Finally, are you sure the F5 is using it's management IP, as in the IP configured on the management interface of the F5 or are you referring to it's self IP on any given interface?