Most likely just a glitch, relax.
Unplug the AC adapter and let your laptop drain the bat to e.g. 94%, then plug AC adapter back in and it'll charge and indicate 100% in a short while.
To ensure you're safe though you can do the following: perform several (3-4) total discharge/recharge sequences with your new laptop/battery.
I suppose you'd better invite an electrician to check the power net of your house