forbidden_labels on Epics doesn't seem to work

We have a triage policy that is meant to flag Epics that don't have one of our "R&D" labels, however, since enabling the policy we get repeated comments

The policy is basically a copy/paste of the same kind of thing we have for issues

resource_rules:
  epics:
    rules:
      - name: Flag intelliHR epics that are missing an R&D label
        conditions:
          date:
            attribute: updated_at
            condition: newer_than
            interval_type: months
            interval: 12
          forbidden_labels:
            - "Missing Category"
          ruby: |
            !has_epic_category_label?
        actions:
          comment: |
            This epic is missing an R&D label and has had the
            ~"Missing Category" label added. Please add one of
            [R&D labels](https://gitlab.com/groups/intellihr/-/labels?subscribed=&search=R%26D).

            If you add the ~"R&D:Core Activity" label, please ensure that at
            least one of the sub-category labels have been added too.

            Once you have done that, please remove the ~"Missing Category"
            label.
          labels:
            - "Missing Category"

It should be excluding any epics that have the Missing Category label, or one of our "R&D" labels, but it doesn't appear to be working.

Is this a limitation of the epic support? Or am I doing something wrong here?