Thanks for the topic.
ACF enqueues the Select2 JS library (v3.5.2) on all admin pages where ACF fields may exist (post, term, user, comment, media, etc).
ACF has an action called ‘acf/input/admin_enqueue_scripts’ which mimics the WP ‘admin_enqueue_scripts’ one. The ACF select field listens for ‘acf/input/admin_enqueue_scripts’ and enqueues the Select2 JS.
I hook into the ‘admin_enqueue_scripts’ action with a priority of 20 if that helps.
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