Hi I am having a very similar issue on a website i administrate http://nailsearunningclub.org.uk/
After updating to wordpress 4 the custom fields plugin has stopped displaying values on the frountend on any page, for example:
https://web.archive.org/web/20140624042720/http://nailsearunningclub.org.uk/links/
now looks like:
http://nailsearunningclub.org.uk/links/
At the back end the field editing options all load ok.
We are using the suffusion theme. We have the most up to date version (Version 4.3.9) of ACF.
The shortcode [acf] appears to be linked in to the plugin as that doesn’t display once ACF activated.
We also have Advanced Custom Fields: Repeater Field plugin installed, activating it or de-activating makes no difference.