Here is my understanding of what is going on, and where the confusion lies:

You are associating a work item to a change set that you see in the component history of the "DEVL" stream and later see that the change set shown in the component history of the "PRODUCTION" stream also had that work item associated. The explanation is that this is the same change set item. I.e. a change set once 'completed' (closed) and be delivered/accepted to multiple streams or repository workspaces. So even if you see it in the history of a particular stream, changing the change set (ex: changing the comment, or changing the work item associations) will also have that reflected in the component history of another stream where that change set also exists.

S Gurugubelli, please let me know if this describes what you are seeing, and let me know if this answers your questions or if you have follow-up questions.

Did you copy your production environment DB and put it into prod? If they are using the same public URI or configuration files, you may have updated the production DB.