WP 4.1.1 + ACF 5.1.9.1. Still have this issue on attachment pages slash attachment permalinks. Somehow the attachment image gets included/injected in all following wysiwyg fields after the attachment (as in the footer in my case). This is really weird and if I remember correctly this actually have been solved in a earlier version, so I suspect it’s a bug that has come back.
Let us know if you can have a look on this issue..
Thanks!
