My 2017 does the same thing. Lower miles after a full charge when weather is cold or you have recently done a lot of freeway driving or heavy acceleration.
Weather has warmed and my driving has been limited to town driving lately. A full charge now indicates 55 miles. YOUR driving and ambient temps will go into the calculation of remaining miles on the battery. I read somewhere that 50 mph max will yield the best battery range. I also use "L" when driving in traffic for maximum regeneration when slowing. Better than getting on or off brakes when traffic is stop/go. Unlike a gas engine driven car, the "L" setting won't cause the engine to over-rev, it just increases the braking effect when you let up on the throttle and puts more electricity back into the battery.
The more economical your driving habits the more battery range you'll see when fully charged. Also, the higher you run the temp setting on cool days the more electricity used. I just set mine at 68 and use the seat heater, leaving climate control on "Eco" and "Auto".