I have a late 2016 MacBook Pro with macOS 10.13.2 High Sierra installed. I've had this problem from at least 3 months.
At first, the battery percentage wasn't dancing like crazy but today it happened. When I check my battery capacity with coconutBattery, it is decreasing normally but when I'm looking at macOS battery percentage it wiggles and doesn't decrease normally.
Sometimes, my MacBook crashes when I don't have anything open except Chrome and Discord.