Why can't I bind this event in blueprints?

I have an AI service that wants to listen to a Perception’s “perceptions updated” event. When the service ends I want to unsubscribe from it.

I have attached an image of me trying to attempt to unbind the event.

I read [this piece of documentation][1], but without an illustration of how to unbind an event I don’t know what I am missing. I only want to bind this specific delegate and not all that may be bound to it (via the UnbindAll).

How are you supposed to unbind an event? When I try to hook up the nodes I get “Delegate is not compatible with delegate (by ref)”. Googling this problem I can’t find a solution.

Thanks in advance.