Very hot climate or is fast charging like crazy. Don't forget about that battery warranty:
"LITHIUM-ION BATTERY CAPACITY COVERAGEIn addition to the lithium-ion Battery Coverage fordefects in materials or workmanship, the lithium-ionbattery is also warranted against capacity loss belownine bars of capacity as shown on the vehicle’sbattery capacity level gauge for a period of60 months or 60,000 miles, whichever comes first."
page 8 http://juicedcar.com/wp-content/uploads ... ooklet.pdf
If you can make it drop another two bars you might get yourself a replacement battery which would increase the value of the car or perhaps a potential buyer could keep that warranty in mind. Those bars would have to drop before 60 months.
I would not expect this capacity loss on a 2015 especially when I see your mileage, do you live in a hot place like Arizona in the US? If so you might want to look at an electric car with better battery thermal management or if you really want that 2019 leaf make sure you get a plus which will cost you more but the larger capacity battery may heat up less.