From IP2315 Datasheet page 7:
[Chinese] IP2315 集成充电超时保护：当充电时间超过 24 小时后，会强制停止充电。
[English Translation] IP2315 integrates charging timeout protection: charging will be terminated after charging time exceeds 24 hours.
It is possible that IP2315 asks adadper for lower voltage, 5V after 24 hours. Never had a chance to test this(never got higher than 5V from any USB adapter of my own, plus Rock 3b died yesterday of SoC solder joint failure)