OK, I just got a new battery from ifixit and got the same problem but it was turning off at 30%..
I was able to solve it by cycling the battery. Is annoying but it works:
-Fully charge the battery and leave it connected and charged overnight.
-Then use the laptop until it runs out and turns off by itself. Leave it discharged for about 4-5 hours or more.
-To verify if the trick works, pressthe Power button and make sure you see the "Connect to the power" symbol.
-Then fully charge it again.
After cycling my battery capacity dropped a bit, but at least now is accurate. I recommend doing coconut battery monitor.