Brent,
You shouldn't have to disconnect anything. The default setup in Workfront is for a request to take on the status of the project that its converted from. So when your request is converted to project, the project is likely in Planning. Once a PM sets it to current you'll see your request on the Board go to In Progress. At that point you can move it to the In Progress column as its being worked on. When the project finishes and is closed, you'll see that same request change to Closed and you can move it from the In Progress to the Closed/Complete column.
This is what we do for our Boards. I did test what you did as well and I do get a dup so I'm not sure if that is by design or bug, but not disconnecting should keep that request and converted project synced together as the project's status updates and you'll not have any dups.