I, and apparently lots of other people, received an error in car and app today.
The error in the car is as follows:
Replace battery
You can continue driving. Have the problem checked by your Service Partner.
I heard from the local service manager that there were more than 10 other i4 owners that had received the same error today.
I had the battery tested and everything checked out ok.
BMW must have pushed out some faulty update to our cars, at least regionally. It seems to only affect cars with iDrive 8.5.