I have a 2016 and used to have a 2019, both have never had any issues like this. I did have a nearly identical problem with my i4 m50 which turned out to be bad door gasket. I’ve also had a similar issue when I had the windshield replaced as it wasn’t done correctly.
My 2016 gas ranges from 82-87 depending on which mode I’m in. Unrestricted tank.
To the OP, Alohart is spot on with how useful BimmerCode and odb2 devices are. Plenty of options that make it well worth the money.
In the 3 years I’ve had my i3 I’ve yet to see any other ok the road. I frequently have people ask about the car being as they’ve never seen one either. It’s going to be a horn honking party when I finally see another one on the road. Enjoy the ride!