Question about Digitec GaN 4-Port Quick Charger

I have a pixel 7 on this charger. The charging process is stopped and restarted approx. every 30 seconds. Does anyone know what this could be? 1 usb-c cable is plugged into port 1 and a usb-a cable is plugged in. Makes no difference if it is plugged in externally... So only the phone. Can't be healthy for the battery