The Logbook does not show all events, it drops events where the entity state is not held steady and therefore any events that change for a short period are not shown. It appears there is some kind of debounce logic in the core that is not logging all events unless the entity state is held for a given time period (unknown). The Recorder logs every event in History - as charted in this example, however the very same events are not reported in the Logbook, frustrating 
My use case is a printer log from an burglar alarm panel. Alarm events are reported through an MQTT sensor topic. The data is captured correctly by HA in the Recorder and History but as the events are not shown in the Logger, it’s not possible to list the events. Ideally I would use the Logbook card to filter on the the sensor entity to just show events from the alarm panel.
Welcome advice and guidance on how to fix this debounce/filtering issue.
