Template name does not take effect
Does xyz field name contain underscores?


  Note that underscores in a Field's machine name are replaced by
  hyphens. Also remember to include "field-" in custom field names, e.g:
  field--field-phone.tpl.php.


https://drupal.org/node/1089656

EDIT:
Add a hook_preprocess_field(&amp;$vars) in your theme and dpm($vars) to check up on theme_hook_suggestions array for this field.