Phusion Passenger Rails not balancing request across workers - ruby-on-rails

Question

Below is the output when I run passenger-status on the server
Requests in queue: 0
* PID: 1821 Sessions: 0 Processed: 2971 Uptime: 15m 11s
CPU: 14% Memory : 416M Last used: 0s ago
* PID: 1847 Sessions: 0 Processed: 1066 Uptime: 15m 11s
CPU: 6% Memory : 256M Last used: 2s ago
* PID: 1861 Sessions: 0 Processed: 199 Uptime: 15m 11s
CPU: 1% Memory : 238M Last used: 3s ago
* PID: 1875 Sessions: 0 Processed: 37 Uptime: 15m 10s
CPU: 0% Memory : 196M Last used: 15s ago
* PID: 1900 Sessions: 0 Processed: 7 Uptime: 15m 10s
CPU: 0% Memory : 136M Last used: 33s ago
* PID: 1916 Sessions: 0 Processed: 4 Uptime: 15m 10s
CPU: 0% Memory : 126M Last used: 33s ago
* PID: 1932 Sessions: 0 Processed: 1 Uptime: 15m 10s
CPU: 0% Memory : 132M Last used: 14m 44s ago
* PID: 1946 Sessions: 0 Processed: 0 Uptime: 15m 10s
CPU: 0% Memory : 68M Last used: 15m 10s ago
* PID: 1962 Sessions: 0 Processed: 0 Uptime: 15m 9s
CPU: 0% Memory : 53M Last used: 15m 9s ago
* PID: 1980 Sessions: 0 Processed: 0 Uptime: 15m 9s
CPU: 0% Memory : 53M Last used: 15m 9s ago
The stack we are running is Nginx + Passenger + Rails.
My concern here is as the docs say passenger must be distributing load across the workers present spawned by itself, but as we can see from the logs, only the top 2 workers get all the requests, the rest are just idle.
Also with time the Memory usage by top workers increases.
Is this an expected behaviour?
How can I rectify this, and can I improve performance in any way?
Also my passenger conf is below
passenger_max_pool_size 20;
passenger_min_instances 10;
passenger_max_instances_per_app 0;
passenger_pre_start <api-endpoint>;
passenger_pool_idle_time 0;
passenger_max_request_queue_size 0;

Answer 1

Silly me, I made a comment a few minutes ago and now I found the answer.
Summary: Passenger uses a simple algorithm to fill up the top request whenever possible instead of using round robin, nothing wrong with your application.
The link explains most of it.
https://www.phusionpassenger.com/library/indepth/ruby/request_load_balancing.html#traffic-may-appear-unbalanced-between-processes