Odd thing happened with my razor

I just disconnected it from recharging, i go out maybe a couple of hours passes when i notice the pocket in wich my razor is hot, i reach out and the back of my razor is hottt, i take a look at the battery and it doesn't even have a bar of battery left, i turned it of and apparently it fixed and now it showed two bars of battery.

Yeah....WTF? first time this has happened to me