I had a similar issue on a iphone a while back. I could comment/post but the last message kept being repeated. It randomly stopped and I assumed it was a site based problem though it could have been resolved by a past iOS update. I'd update the ipad if you haven't installed all the available updates and look into other app based browsers. I'd also try viewing the site in a different way, such as the site has a mobile and desktop view, to see if the glitch occurs in both modes.