Battery Shows 60 Percent Then The Controller Dies Minutes Later

The reading is not broken. It is reporting faithfully, and what it is reporting is a worn cell.

Controller battery indicators do not measure stored energy directly. They measure voltage and map it onto a percentage using a curve for a healthy cell. A new cell discharges along a predictable slope, so the mapping works and you get a gradual decline. As a cell ages its internal resistance rises and its discharge curve changes shape: it holds a reasonable voltage for most of its remaining capacity and then falls off a cliff near the end. Run that curve through a mapping designed for a healthy cell and you get precisely your symptom, long plateaus, sudden drops, and a death that arrives much sooner than the last reading suggested.

The steps you are seeing in the test are the honest consequence of that. Two and a half years is a normal point for this, especially if the controller is often left on charge or run flat regularly, both of which accelerate it.

So the fix is the cell, not the firmware or the indicator. If you are using a rechargeable play-and-charge pack, replace the pack, which is the simplest option and needs no tools. If you are on AA batteries, a worn set of rechargeables does exactly the same thing, and a fresh set of good quality NiMH cells will restore a sensible curve. Worth knowing: cheap AA rechargeables and partially worn cells are the single most common cause of this complaint on an Xbox pad, and people replace controllers over it.

One thing not to do: ignore the plateau and trust the number. Until you have replaced the cell, treat anything under about 50% as near empty, because the indicator cannot give you a useful warning on a battery with that discharge curve.