A particular Action Item cannot be deleted from the UI by an admin because the associated Risk was already deleted which has left the AI as orphaned. The record still exist in the action item table as below
select *
from CAL_ACTION_ITEMS
where object_id = 5029001
and sub_object_id = 5033051
Shows that the Action Item is for CAL_RISK, however, there is no Risk with ID = 5033051 (sub_object_id).
Release : 16.1.0
Identify the Owner/Assignee of the AI from the above query and login as that user.
Once logged as the Owner/Assignee of the AI, the record can be deleted from the UI.