Thank you guys for a quick response. It happened again last night. I am using Apple TV2 and when I went onto youtube the mouse pointer moved sporadically and the video was choppy and stoping (not loading) stop and start all within a second. What I did was to eventually and with some difficulty close out and quit Safari leaving my desktop on my TV screen. I see now that the mouse is now moving freely and smooth and I reopen Safari and connect to Youtube and and everything worked fine.
When I'm done watching Youtube I just grab the TV remote and select input #1 to go back to regular TV without closing or quitting airplay and selecting disconnect from apple tv. Could that be whats causing the problem?