If an event is skipped due to old age, but the time looks correct, check to see if the opeventsd was running at the time the event was received.
Need a flow diagram of how and why the many opEvents rule processing files are processed.
When troubleshooting event processing it's useful to understand the order that the various opEvents configuration files are processed in and the general function of each one.
When troubleshooting state it's important to realize that event.event and event.stateful are two completely different things. event.stateful is referred to as 'State Type' in the node context view. State is tracked based on event.stateful only, state status is generally up or down and may be found in the value of event.state.