Unexpected SYS Drop on MP2632 EVM When USB Source Is Plugged In

Hi,

We are using the MP2632 EVM, powered by a battery, with the micro USB port initially left floating. The SYS output is connected to an electronic load set to 200 mA. I observed that when a PC or USB adapter is connected to the micro USB port, the 5 V boost output on SYS drops to 0–1.5 V. The voltage only recovers to 5 V after the electronic load is turned off.

Interestingly, when using a bench power supply instead of the USB port, the system operates normally.

Is there a recommended way to resolve this issue?