I have that happening too. I know that when the bars are centered (TV going straight) that the spring bar is touching the cam in only two places as opposed to sitting evenly on the cam. I needed a feeler gauge to tell.
Here's a photo:

See how the it is most shiny on the top right side of the spring bar(rear) and on the bottom left (front)?
Those shiny areas are where the spring bar rides on the cam. I assume that over time it will wear in where both parts match up better and the bars will release freely.
Here's the wear on the cam arm:

Is it possible your bars are contacting in a similar way?