I'm still dealing with this. One trick I've learned to use until Imgur fixes this is that if I refresh the page, while it's loading, I can upvote on comments that have loaded, post a comment, or I can save images to iPhoto. I can also upvote photos by viewing them in thumbnails in the gallery. I've also been able to view comments by holding the "+" icon by a comment and then selecting "open" to view replies or post a reply. I hope this gets fixed soon. I was emailed by Imgur around a month ago and was told they are working to solve the problem. So, fingers crossed.
Customer support service by UserEcho