Flag ajax link triggers ECA workflow then resets

1. Create a Task content type.
2. Create a Task Log storage entity type.
   1. Add a Task reference field.
   2. Configure automatic label: [storage:field_task:entity:label] - [storage:created].
3. Create a Task Complete flag type.
   1. Ajax link type.
   2. Configure for Task content type.
4. Create Log Task ECA workflow.
   1. Event: Flag
   2. Action: Create Task Log entity
   3. Action: Set Task Log Task reference field to flagged entity.
      1. Save Task Log.
   4. Action: Preconfigured: Delete flagging

Now there should be a flag button on your Task. When clicked, this will create a Task Log storage entity and reset the button, allowing you to click it again.

Next steps:

Indicate that the button has been clicked by setting a message.