Apparently the calibration is correct (as stated by @keesj elsewhere). It just seems that the batteries’ quality is quite low… Some people reported bloated batteries, and some other posters in this thread suggest, that it started with a wrong charging status.
I think that maybe 25% of the battery’s energy capacity are defunct and cannot provide energy anymore. IMO it’s not a big deal. The worst is a bloated battery, in this case stop using it immediately (it can explode)!!! 