It will be never be fixed, as you really cannot measure exact digital values from analog battery. So its just a common feature of li-on batteries that voltages drops rapidly on when battery level gets low. So there really is not anything that can be fixed.

Well they can fake the sw not to read the battery levels and only show decreasing values that has nothing to do with battery level. But imho its better to show what battery reports as voltage level than to lie to end user in the UI.