Safari Problem.

Hey, recently youtube has not been playing correctly in safari. I have a 2011 macbook air and everything is at the most recent update including safari. I have a youtube bookmark for my subscriptions box and i frequently use it to check out new uploads. The problem is that when i click on a video it doesn't start i have to refresh the page to start it, however if i click on a video on the side or search for one it automatically starts like normal, until i go back to the youtube homepage. Sometimes the video will not play no matter how many times i refresh the page (this happens when i click on a youtube link from another page). Any help will be appreciated thanks!