Calling an event dispatcher without bindings should show a warning after playing like when trying to do things without valid variable references. Sometimes it's not clear if the logic or bindings are failing, it would be easier to fix problems if you know that the binding didn't happen before the event dispatcher was called.

That seems a bit random too btw, for example I had two different animation BPs where I was assigning an event dispatcher in one of them and calling it in the other on initialize animation. The event dispatcher was called first which obviously stopped the event dispatcher from working at all. It would be nice if things like binding event dispatchers/creating variable references (that are then used) would be prioritized, right now you have to put Delay nodes everywhere which kind of feels like a band-aid.