IRules Using "LB:status" to manage traffic - round robin issue

Hello Community, Below is the set of IRules I have in place.

  Determines which pool member to route traffic too
if { ([LB::status pool www.qad.com_pool_80 member 192.168.254.189 80] eq "up") } {
     Routing to primary or fail over server
    pool www.qad.com_pool_80 member 192.168.254.189 80
   return
} else {
     Routing to primary or fail over server
    pool www.qad.com_pool_80 member 192.168.254.103 80
   return
}
return

I found that every few minutes traffic get's routed to the fail over server "192.168.254.103". The load balancing method used is "null" and there are 2 health monitors applied to "192.168.254.189". 

/servername.txt  - Looks for string "ACTIVE" in return every 30 seconds
/erp/ - Looks for string "QAD" in return every 30 seconds

They both are green and is (should) not flagged is down unless homepage errors out or admin manually changes the txt file. I'm not sure why the "LD:status" would NOT be "up" in this test case.

Any thoughts or gotchas that I am missing?

Thanks.

Traolly Xiong