I have a similar case, but the key is a User object field called “consultant”. A var_dump of the get_field results in a array of user data.
Is type of field serialize data too?
This LIKE compare doesn’t seem to work, but then again neither does the “IN” which I would have thought was the correct compare?
Details here -> http://stackoverflow.com/questions/26768230/wordpress-meta-query-on-user-object
Thanks