As a temp fix, you may comment out the inclusion of ACF’s date_time picker in the file: acf.php on line 224:
This will prevent ACF from including it’s own, and you can continue to use the 3rd party one.
Can you please check your DB wp_postmeta table and view the value that is stored by the 3rd party field?
What is the value?
– ACF PRO saves the value like so: YYYY-MM-DD hh:ii:ss
– If the values are similar, they should be compatible
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