It looks like in some environments, like WPEngine, ACF skips using any caching mechanisms.
We’re using ACF with WPEngine with ‘Object Caching’ enabled, and ACF skips caching entirely resulting in all calls to ‘get_field()’ being pulled directly from the DB. When we disable ‘Object Caching’ ACF uses the transients API, and it works much more efficiently.
Is there a way to properly make ACF use ‘Object Caching’, when enabled?
I have experienced a similar issue (or at least related to caching). In a new website with the latst ACF Pro hosted in Siteground, activating their own caching plugin called SuperCacher breaks the ACF UI and all field group appear as inactive. Removing the plugin does not help, you have to also remove the object-cache.php from wp-content and delete the cache folder. I suspect the issue was because i enabled memcache but i am not 100% sure. This might be relevant to the above question
Please ACF team address issues with object-cache.