I'd be happier with the diagram if Honda would verify what's happening when the ICE starts up in response to regen braking when the battery is already fully charged (Zero-Regen Braking in the chart).
Per my Scangauge, the battery is always either supplying energy or getting charge. I have noticed that between -3 and 3 amps, the flow meter it not always accurate. It either shows the correct flow or nothing at all. Sent from my iPhone using Inside EVs