I’ve had the same problem after the last update of the plugin. So I did a lot of different tests and it seems there is a issue with the add_action WordPress function.
The thing that causes the admin menu not to show is this line (acf-options-page.php line 44):
add_action('init', array($this,'init'), 1);
It seems the whole thing breaks as this init add_action has a priority set as 1, while another init add_action in the acf.php file (line 81) is also set as 1 in priority. So if one simply change the priority of the init add_action function in the acf-options-page.php file to 2, it all works.
Hope it works.
Daniel
