The current behavior is consistent with 12.04, but these new & improved icons make the problem easier to see.
Looks like the battery-full-symbolic, battery-good-symbolic, battery-low-symbolic icons are getting used first. Daniel's apparently seeing the drop from -full to -good, which in the icons appears as a 50% drop.
Placing the percentage-based icons higher in the iconname list for g_themed_icon_new_from_names() ought to improve this.
The current behavior is consistent with 12.04, but these new & improved icons make the problem easier to see.
Looks like the battery- full-symbolic, battery- good-symbolic, battery- low-symbolic icons are getting used first. Daniel's apparently seeing the drop from -full to -good, which in the icons appears as a 50% drop.
Placing the percentage-based icons higher in the iconname list for g_themed_ icon_new_ from_names( ) ought to improve this.