We have a kenmore fridge with the freezer at the bottom. Not sure on how to explain this - but the fridge door no longer shuts tight without some force. Before it used to have a 6" gap when teh door had some tension and then automatically shut tight with out effor. Our bottom door is okay.
I also could not find any cams so it looks like they do not use them on this unit.
I did find a part they called a stopper (243) perhaps something is wrong with that.
Also check the gasket/seal on the hinge side of the door. Sometimes they can grab and cause problems. A light coating of white lithium grease or vaseline usually fixes this.
Other than the above I am afraid I am out of ideas.