Skill Based Routing : Omni Channel Changing case owner to agent whom it was routed to even if agent 'Declines' work Item or even if work item gets 'Timeout'

To check this behavior in your demo org:

• Enable Omni Channel Skill based routing
• Create 2 service cloud users and then create Service Resource records
• Assign required skills to Service resources
• Make User 1 online and User 2 offline from Omni
• Create a case which meets the criteria(we need to create trigger/process builder with helper class ) to create PSR and route the work Item to agent
• Case will first routed to agent if agent didn't accepts the work item, we all are under the impression that work item will route back where it actually originated
• But our assumption is not right and below is the explanation.

The behavior of declined / push timeout work continuing to be owned by the agent that it was routed to is WAD since no qualified agents available and there isn't really a queue to go back  , however the PSR continues to exist because agent didn't' accepted the work item . 

The work won't route back to you until you change your status. Even if the case sits in User1 queue and if you flip the Omni status , you can see the work item route to you and the same you can find in your widget. Else if any other qualified agent comes online the work Item will be moved from your queue and it will sit in the second agents queue , until unless either of you accept.  If you had another agent online with the necessary skills, it should go to them when the decline / push timeout occurs.