The MAX17263 is a fuel gauge with built in LED control. THe part offers a feature called Auto LED Counting, which automatically senses how many LEDs are connected to the device. This feature is triggered automatically at startup and can be manually triggered by resetting the device and setting the EnAutoLEDCnt bit (in register LEDCfg2 0x04B).
The Auto LED count feature does not work if the part has noticeable load or charge current because the load/charge current will get mixed in with the LED current, which makes detection impossible.
When using this feature, please ensure that there is no significant load or charging current present.