Sadly, this is a known issue with the 30kwh Leafs, and you will likely lose that fourth bar this Summer. That's the good news! The bad news is that your free replacement pack will likely lose capacity just as fast, making buying the car off-less unappealing. To speed the loss of that 4th bar, try to keep the pack "Hot & Full" as much as possible. Then try to keep the new one "Cool & Comfortable" with less than 100% charges except as needed.
2013 "Brilliant Silver" SV with Premium and no QC, a 2009 Vectrix VX-1 W/18 Leaf modules, and 3 EZIP E-bicycles.
PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.