Sooooo I have a workaround:
remove_action('post_updated', 'wp_save_post_revision');
...
wp_update_post($postData);
...
update_field('field_XYZ123', $value, $post_id);
...
add_action('post_updated', 'wp_save_post_revision');
And it works apparently, on the other hand we have no revision during the post update…
So the real question (I think) is the following:
Why get_field() called in WP theme doesn’t retrieve the same Post ID than the one retrieved from the Back Office?
