Yoast options not showing on posts or pages

I just noticed that the WordPress SEO options are no longer editable on posts and pages. The title bar is still visible, and the menu says it’s expanded, but there is nothing there. I can’t add SEO info to new posts/pages, and although the SEO lights show that all my old posts and pages have info, I can’t see or edit it either.

I’ve updated to WordPress 4.1, deactivated then re-activated the plugin, made sure it was the most up to date version, restored the default settings and that hasn’t worked. I’ve been told another plugin could be responsible for the widget not being visible, but I’ve only installed one new plugin in the last four months, and this seems to be a recent thing.

If a faulty script is to blame, what’s the best way to go about identifying the problem and taking care of it? Any help is appreciated.