HOWEVER, 99% is close enough, and often on a new device the charge controller is not calibrated perfectly.
Run your phone to exhaustion, to the point where the phone shuts itself off.
Then plug it in, and leave it alone to charge it fully.
Then use normally.
(This is not recommended as a daily use routine. Its something you do once in a while, like maybe every three months or so, and usually it will happen enough by itself that you don't need to do it).
Mine was doing fine all week off the normal charger. Got a external battery as a "backup" and played with it last night. Could only charge to 99% even after putting it back on the real charger. Hmm