This appears to be an issues with how your Application's load Balancer handle disbursing the load. IF Load balancer is disbursing base on IP then you must configure the IP spoofing properly

Currently your test scenario (as descripted ) is only using 2 ip's one from each Generator so all Vusers on a give generator are using the same IP.

Having IP spoofing on and only one IP per generator is tell the controller to pick a IP for each Vusers from a list of IP that has only one IP. Thus all Vusers get the same IP and the load balancer is sending to the same app server

To use IP spoofing

1. On the each Generation, Run the IP wizard to assign mulit unique IP's
So Generator 1 would have, example
10.11.125.001
10.11.125.002
10.11.125.003
10.11.125.004 to
10.11.125.100

Gene 2 would have multi unique IP's of
10.11.125.101
10.11.125.102
10.11.125.103
10.11.125.104 to 10.11.125.200

2. On the Controller
a. enabled in the controller scenario

NOTE

Once the generators having multi unique IP's assigned the scenario when ran will have the controller assigned
each Vuser a IP from the list of available on that generator

If 200 IP's total (100 per generator) and 300 Vuser. The Controller will use all the IPs
in order and then start over with the first IPs when it reaches Vuser 201