Media not displaying in new posts/pages

After the update to 4.4.1 it seems media cannot be loaded to posts or pages. They appear just as the media text in the post itself.

When the class (class=”aligncenter size-medium wp-image-2459″ for example) is removed the images are displayed as normal.

We are using twenty-twelve theme, tried deactivating plugins but it made no difference.

Thanks
Lynn