Hi Elliot.
Unfortunately, I didn’t have too much time to really find what causes the problem. I just compared the final HTML codes of the ACF Option page: with active Formidable and without. I found that we miss those scripts when Formidable is on. It re-declares the scripts somehow.
Since I needed some fast temporary solution, I just linked those 2 scripts “manually”. By and large, we miss some other scripts too when Formidable is on, but since these two were enough to make link button work, I stopped on them. I also don’t know where ACF registers these two or maybe WP itself does this for all admin pages? When I have more time, I will study this problem more carefully.
Sorry for not being too helpful.
