So as I posted with the partition/separator issue, the screws that hold the tab/hook that goes into the latch are stripped and loose. The tab piece is a bit loose, so probably not helping the problem. The screws are in good shape, it is the holes which seem to be plastic. Does anyone have a stripped screw repair for plastic idea? I hate having to buy the entire trunk floor folding mat replacement. Thanks.

Well, looks like wrong initial diagnosis. Even though the right latch for the partition was weaker than the left, the problem was actually loose tab/hook piece on the partition. This didn't allow it to seat properly in the latch mechanism. The main cause of all of this was too much junk piled up on the right side of the compartment under the mat, which created asymmetric stress on the right side. Sorry for wasting anyone's time who read this. Based on this being my wife's 09 car with only 18,000 miles, I suspect will will be a problem for others. Thanks for looking. PS. I superglued the tab to the mat, put some toothpicks and glue in the screw hole. So far working for a few hours. I expect I will be buying a new mat one of these days.