I’ve noticed an issue with the back end admin for ACF. I think it’s been around for quite a while; I can confirm it’s still present as of v. 184.108.40.206.
I have a “starter” theme I use when I’m building new themes, and it includes an acf-json folder where I keep field groups I use regularly.
I want to sync these field groups, so I can make site-specific edits, but I’ve found that if there is not already at least one field group created, the “Bulk Actions” dropdown with “Sync”, and the “Apply” button do not appear on the “Sync available” page. Creating a field group and then returning to “Sync available” makes those form inputs appear.
I think the problem is that these are modified by jQuery in admin/field-groups.php (lines 769-779) but that’s assuming that the Bulk Actions dropdown and Apply button already exist on the page, and they’re not there when there are zero existing field groups.