On AIX for example, you have two active NICs, en0 (10.128.2.5) and en1 (10.128.2.8), and you configure a third NIC, en2, as the backup NIC to en1. The agent does not fail over from en1 to en2 because some ping tests are redirected through en0 on the same subnet, making the MultiNICA monitor return an online status.