I have ACF running on a site with 4.3 and I’m not seeing any issues.
Trying to understand what’s going on, is that publish button always inactive or does it become inactive when you click it and it gets stuck there?
There is more than likely some incompatibility with another plugin or your theme. What you need to do is deactivate the other plugins on the site and possibly switch to another theme to find out what is causing the problem.
