GTM Topology pointing to incorrect region

Scenario:

I am using topology based load balancing mode to lb traffic between 2 different data centers (say A and B). Under wideip I created 3 pools (A_pool, B_pool and FALLBACK_pool) and created 3 topology records. config as follows.

 

WIP level LB is Topology and persistence is enabled with ttl persistence value as 1800 Pool level LB is Round Robin with ttl as 30

 

Pools:

A_pool --- LTM VIP and 2 pool members under that vip are apphost members ( all pool members status is UP and running ) B_pool --- LTM VIP and 2 pool members under that VIP are apphost members ( all pool members status is UP and running ) FALLBACK_pool --- 2 LTM VIPs ( A abd B )

 

Topology Records:

Anyone uses Region 1 DNS will be directed to A_pool with --- order(600) and score(40) Anyone uses Region 2 DNS will be directed to B_pool --- order(599) and score(40) Unmapped will be directed to FALLBACK_pool --- order(1600) and score(20)

 

Region 1 has 3 or 4 subnets Region 2 has 3 or 4 subnets

 

the question is, the traffic is directed to only A_pool irrespective of which region is used , which is pinging from DC "B" is directing the request to A_pool instead of B_pool. I am confused. can anyone help me on this scenario and please provide your comments on the config and what needs to changed in order to make this right.