Default Battery calibration problem.

I was playing with my tablet last night with what I thought was 60% battery left when it suddenly turned off. I thought at first it will reboot but no it didn't, not even if I press the power button to start it up. It was only after connecting it to the charger that it finally powered up. It was a surprise that the battery showed it is at 0%. I charged it to full and then disconnected it.

Now the problem is that it is stuck at 100%, both in the status bar display and when checking in the settings and then battery. Any insight to this issue?

Stock, rooted but not unlocked.



UPDATE: After reading around with posts of the problem similar to mine, I tried a suggestion of turning the tablet completely off for at least an hour. Others did so overnight. I chose to power it off for an hour and now it is already discharging. Maybe this is a bug or a hardware fault, no one can tell for sure.