Unable to turn screen on unless charging

So, my dad recently had his Pocophone F1's USB port replaced, but now we have a very different issue. When the screen turns off, due to pressing the power button to lock the phone, or waiting for the timeout, the phone is unable to wake up again by pressing the power button. The phone is still powered on, as it can make notification sounds. If plugged into a charger, then the screen turns back on and the power button works normally, all the apps that were open are still there so the phone was clearly not powered off. If not plugged into a charger and the screen is off, pressing the power button does nothing. You have to long-press the power button to cause the phone to reboot, then it can be used again until it is locked again. Is this a hardware issue, or a configuration problem? We already tried sending the phone back but the repair person was unable to fix this behaviour. OS: MIUI Global Stable 12.0.3 (stock ROM) on Android 10.