I actually solved my problem with WYSIWIG ACF not showing up on taxonomy with this code – basically having to pass the taxonomy and post id in the get_field parameter. This only seems to be necessary on the WYSIWIG field, all other field display with out this.
$queried_object = get_queried_object();
$taxonomy = $queried_object->taxonomy;
$term_id = $queried_object->term_id;
$post_id = $taxonomy . '_' . $term_id;
$custom_field = get_field('MY-ACF-FIELD-NAME', $post_id);
echo $custom_field;
Did you get this solved? I have a custom taxonomy with several ACF attached to it. For some reason one of the fields, a WYSIWIG never shows up using get_field, and only ever shows null if I printr it. I have deactivated all plugins but nothing I have tried makes it display.