Ok, sounds like you haven't encountered the issue because you don't have notifications setup. You don't really need iPhone for that, as matter of fact I don't even have one, it's managed via CARWINGS
web UI. Also, it doesn't matter what charger you have either.
If you don't mind doing a test that would much appreciated, I would hate to bug dealer again if this is common thing.
The two scenarios that I used:
1. Enable notifications in the web interface (https://www.nissanusa.com/owners/login
2. Set 80% timer
12:00 am start 11:50pm end (or your preferred times are ok)
3. Plugin your car to charge as normal and make sure it charges to 80% before timer
4. You should get notification that your charge stopped with 10 out of 12 bars
5. At 12:00 am you'll get second email that your charge stopped with 10 out of 12 bars
If you don't enable notifications, be next to your car when the time reaches the timer
's start time.