Please share the possible reasons about this behavior of queues and worker?

I noticed something similar when we added some extra workers and the last worker in list is online but not busy I found an article recommending to have 1.3X more queues than workers, 

Hi,

There is dedicated article explaining how publisher queues are utilized for publishing Article - CS42096 - What is the Mechanism of the Publishing Jobs are assigned among the Priority Queues, Numbered Queues, and Workers? (ptc.com)

If all the jobs are going to single worker, then most likely it is configuration issue. Try to validate :

- all configured workers are running and enabled with auto-start

- additional queues configured adhere to pre-requisite. Refer above mentioned and other https://www.ptc.com/en/support/article/CS43769 

- if you still face the issue please contact Technical Support team, they can help such scenario

Here you can see jobs of my workers:

I believe the CAD agent does scheduling by looking at worker1 always first, then if busy worker2 and so on. This ends up with worker1 doing the most jobs even when the number of jobs exceed the workers. I had mapped this out a while back and it showed law of diminishing returned kicked in at some point. You would obviously need to tune this to your users and system. 

Can you explain more about the "concurrency" issue in your BGMS? Are you seeing red there? Perhaps there is some additional tuning needed there, Screenshots.