More specifically, when they click tag checkboxes they get the message "API permission check failed for EntityTag/create call; insufficient permission: require access CiviCRM and edit all contacts". However, they are able to tag users after clicking the "Edit" button.
The solution offered by the error message (enabling, in Drupal, the ability to edit all contacts) is not practical for me since it also allows them to view all contacts (which is against our internal policy).
A little more info on my permission structure in case it's relevant: My ACLs allow users to view and edit contacts that are members of certain groups. Ex: A user named "Bob" is in the group named "Staff". Those in the group named "Staff" are allowed to view and edit contacts in the group named "Universe".
As admin, I don't have this problem. But when I log in as a lowly user I do.
Drupal version: 7.37. CiviCRM version: 4.6.3. Thanks in advance for any help.