Hi everyone! Anyone experience a stuck, or non-returning, electrical contact pin before? It is how the camera body communicates with the lens, and on my 5D MKII one of the gold pins is not 'returning' to its position, looks like it is stuck or perhaps the spring mechanism isn't working to return it. Consequently, the camera body doesn't register that there is a lens on, with no autofocus or change of F-stop. Ugggg! Thanks, Ryan.