My leased 2017 Bolt would typically charge up with 268 miles, sometimes a bit more and sometimes a bit less. I live in San Francisco with a lot of city driving, so I get more range than the listed 238 spec. Now I have passed 13,000 miles and the last 3 charges have given me about 230 miles after a full night of charging at my level 2 station at home. This seems like a substantial drop: is there something wrong and if so, what could it be? What ought I do about it? This is about a 15% drop for a pretty new car.
As others have already pointed out, everything is fine. The range meter drives folks crazy because of the expectations of it being accurate and consistent. It's neither. The Bolt's battery holds the equivalent of a bit less than 2 gallons of gas. So even small changes in efficiency has big impacts on the estimated range.
I have a Fiat 500e, with a battery that's a third of the size of the Bolt. There are days now where full range is under 80 miles when in the summer it shows 110. The two items I actually pay attention to is the actual battery percentage and the trip efficiency. There are very good days starting with a warmed battery with nice conditions and no HVAC where the efficiency is 4.8 miles/kWh. On colder days with the heat on and a cold soaked battery where a short trip will show as low as 2.1 miles/kWh. Nothing has changed with the battery. Only the conditions has changed.
This efficiency issue is true of both EV and ICE vehicles. But ICE can carry 8 to 10 times the amount of fuel, so the efficiency deficits has much smaller impacts on range estimation.
So as others have pointed out, nothing is wrong with the battery or the range meter. As long as you can get to where you are going driving the way you normally drive, then there is nothing to do. However, if you really want to test the theory, simply drive 5 MPH slower than you normally do, and precondition your Bolt while it's on the charger. Watch the GOM then.