Thak you for your apperciation.
The *ObserveReactComponent *was ment to have everything it needs on begin play, so the event binding is done on BeginPlay. If you add something afterwards, it will not work. This is becase, depending on the selected aggregation method (*Passthrough, Aggregate *or *AddTobuffer), *more calculation is done on Begin Play based on the number and the state values of the actors from the ListenTo array.
But, assuming you want to have A reacting to B state changes: instead of adding B to the Listen To Array of Button A, maybe you can add A to the *Send Actions To *array of button B. Let me know if this works.
If the above solution does not work, It would be great if you could send me an email with your setup, and tell me exactly what you want to achieve. I could, then, provide more guidance, or, if possible, I could include something in the next asset release that might help with your game.
Have a great day!