Apple's newly rolled-out iOS 26.4 beta versions, namely Public Beta 1 and Developer Beta 2, have captured extensive attention. Some users of older iPhone models have reported a notable decrease in charging speeds, along with failures in fast-charging functionality. Upon testing, it was found that the problem mainly impacts models that still employ the Lightning port, like the iPhone 13 and 14 series. Users noticed that even when using high-power fast chargers, their devices only charged at a very slow rate, with power around 7 - 8W. This significantly prolonged the charging duration. A technical analysis shows that the root cause of the problem lies in a bug within the underlying code of the new system. This bug prevented devices from recognizing the USB PD fast-charging protocol, leading to an incorrect locking of the charging power at a low level. Subsequently, Apple released iOS 26.4 Beta 2, which specifically tackled this fast-charging anomaly. After the update, older iPhone models resumed normal charging speeds. This incident serves as a wake-up call, reminding us that beta systems may come with inherent instability risks. It is advisable for users to thoroughly assess the upgrade options before proceeding and stay tuned to community feedback to avoid any disruptions to their daily usage.