The CheckEvent condition is implemented so that whenever the target event is received, the CheckEvent condition will return true for one frame. It does not latch/keep it’s value, but if it’s next evaluation happens on the same or next frame apart from when the event was received, it will still return true. After 1 frame has passed, it’s return value will reset to false, until the event is received again.
I think that for your case where you want to have nodes being reset and re-evaluated within same frame as far as I understand, it would be better to work with boolean variables rather than events, since events within the context of Behaviour Trees, are a bit tricky due to how Behaviour Trees work in general.
Gavalakis
