i have read that overcharging a lithium ion battery will reduce its effective life and have seen this case with G75 models due to smart-charging technology which preserves the life of the battery. Frequent 3% charge/discharge wears out the battery prematurely, so ASUS is protecting your battery for you. You don't have to worry, that is perfectly normal.
I have had my ASUS ROG G750JW-DB71 for three months but only used it for one month due to hip operation and the fact that after one week of usage I had to send the ASUS back to XOTICPC.com who sent it to ASUS and supposedly replace the motherboard. My battery got up to only 87% and now is completely dead. Xoticpc wants me to pay again to ship the defective battery back and then send to ASUS. Filed a case with ASUS but nothing yet.