Our BMW i4 does this too, but I usually charge fully (80%) anyway to provide more margin for error. Electrify America stations (free for 2 yrs. with BMW) aren't as plentiful as Tesla Superchargers, and I've encountered entire stations being out of service due to maintenance. I've always been able to charge elsewhere, so it hasn't been a major problem. And EA stations are getting more common and reliable, so it's getting easier and easier over time, which was my hope when we leased the i4.
Example: About six weeks ago, my wife and I planned a day trip to southern Delaware for our anniversary. I thought we would need to charge at Blink or Chargepoint in central Delaware on the way back to Philly, unless we could make it to the EA station in Wilmington. About two weeks after we made our plans, EA opened a new station in Dover, which was simply perfect. It was a completely stress-free trip.
Similarly, some of our more frequent road trips go into rural Sullivan County, Pennsylvania to visit friends with a house there. After we had driven our i4 there a couple of times, EA opened a station perfectly placed in Bloomsburg, Pennsylvania. Now, it's simply no problem to charge on their regular house current while we're there, and top up in Bloomsburg if necessary on the way home. Last year, we charged to 90% in Bloomsburg, then made it to West Orange, NJ to visit relatives, then all the way back to Philly, all on a single charge. It's fantastic.