Why is it that when we Route Work skills based does it keep it with the original owner until it gets to the top of the PSR/Backlog queue, but when doing Queue based it changes the owner to the queue immediately?

please can anyone help?   

The current scenario is the following:

• Case Exists and is waiting on customer, with an agent assigned as the owner at that time
• Customer responds and case transitions to 'Response Received'
• Case is picked up and put onto the queue, however the system then removes the Owner

I would like the desired flow to be as described below:   

• Case Exists and is waiting on customer, with an agent assigned as the owner at that time
• Customer responds and case transitions to 'Response Received'
• Case is picked up and put onto the queue, with the agent owner retained
• If the piece of work gets to the top of the queue and is pushed to a different agent via Omni then as per standard omni process the owner is changed