Yes, that's true, that is normal and quite usual situation. But after engine is off, there could be no more off block and take off. But I can imagine the case with SD being still on and logging someone's consecutive flights from A to A, like sightseeing flights, without any need to manually log it every time. So it shouldn't stop logging after on blocks. That solution is not so obvious. As for now I see two possibilities:
1. No automatic off-block and take-off after the engine off is logged. To log new flight, user would need to manually log engine on again, or return to planning mode and back to flight mode again. It may irritate some users, and potentially cause some unlogged flights for them (some may forget to log engine on, the same like I forgot to go back to planning mode...). But on blocks should not stop further logging - it's not enough.
2. Don't touch the logging mechanism and let it work without any changes, as it works well. But to avoid unwanted logged "flights", just let the users to remove them by splitting the logs by block times logged. If we can merge the logs, let us also split them. And then, after we split off the erroneous flight log, we could delete one, saving the correct part of the log (from engine on to engine off, or off blocks to on blocks). It don't expect that to cause any negative outcome, however I can be unaware of something. Maybe that would be the best solution?