Why are you using multiple NIC's on different Subnets? Orion can see through the subnets without being directly attached, providing your routing is setup correctly?
If you team the NIC's for increased bandwidth/performance rather than failover it will also help.
If Node A
some nodes in our network have multiple network adapter . some times give me on alert that the node is down but it is up.
EX:
node A have 2 ips:
192.168.50.50 is down
192.168.30.50 is up
and i got many nodes which have 192.168.50.** are down ,
Would that not suggest you have a problem with that subnet?
Are you also rolling up the status so that is shows the worst status, so in this case you have 1NIC up and 1NIC down, this would show node down as an interface is down.
Just thoughts...