It does sound like Glance Background is on... Check that in Settings > glance background
Also, try a Soft Reset. Hold the Volume Down + Power buttons until the phone vibrates and reboots (about 10 seconds). You may just be having a small glitch getting the battery to update status...
Finally, try this free App. I find it very useful for analyzing charge and discharge on Windows Phone and, IMHO it offers the best Live Tile info especially on largest tile.
Battery | Windows Phone Apps+Games Store (United States)
If none of that helps use your warranty as gpobernardo advises.