Under certain cases, player interactions fail to call the relevant listener. This tends to occur when a given players block interaction range is greater than their entity interaction range, resulting in any attempted entity interactions, such as an attack, between the block interaction and entity interaction ranges to trigger nothing. This can be quite easily replicated if you lower your entity interaction range below your block interaction range, then attempt to hit an entity between those ranges, resulting in no event handlers being triggered, or at the very least, none of the entity interaction or damage handlers.