So I've had my 6D going on 2 years now about a month and a half back the farthest right AF point stopped working. Its tries to focus but hunts for a really long time. I have tried several other lenses and all the other points are pretty snapy but not this far right point. I have tried cleaning the contacts and updating to the newest firmware with no luck. I'm thinking I'm going to have to send it into canon for service unless I need to clean dust off the sensor or something?