Why is ACF using the plugin version for the select2 script version? The big issue here is select2 is being registered using the plugin version and not the select2 script version. You should always use the script version when you enqueue – that way if another plugin is using the script, WP can compare versions and use the newest one.
https://developer.wordpress.org/reference/functions/wp_enqueue_script/
This needs to be changed to avoid compatibility issues with plugins in the future.
