Hi @rowatt
Thanks for the clarification.
Just to consolodate the info: You are using the acf function acf_add_options_sub_page to successfully add an options page to the wp-admin. This works fine, and you are now attempting to add a normal admin menu item to sit along with it.
I think the main issue is that your action is running before ACF’s admin_menu. If you look at the code within the options page add-on, you will see that the admin_menu is run with a priority of 11 which is AFTER your default 10.
Perhaps if you were to increase your priority to 12 or above, you would be able to attach your menu page correctly?
Thanks
E
