Okay, it was a simple fix. Until an patch is released for ACF, you can do the following:
Open up [WP DIR]/wp-content/plugins/advanced-custom-fields/core/fields/taxonomy.php
Edit lines 415, 419 and 424 and replace value="' . $term->id . '"
with value="' . $term->slug . '"
Hope that helps. 🙂
This is an issue with WP1.6, I think.
I ran into the same problem when writing a custom import script. It seems when running wp_set_post_terms
you must use term names (slugs) rather than IDs.
Only the categories
taxonomy uses IDs, now.
Ref: http://codex.wordpress.org/Function_Reference/wp_set_post_terms
It seems the ACF plugin is setting the terms using the term IDs, rather than the slug. If that’s the case, should be a simple fix. 🙂