Letting usb-otg2 suspend increases power consumption

I can consistently see power consumption increased by around 70mW once usb-otg2 (internal USB bus) gets suspended; it goes back to normal after waking it up - which is the exact opposite of what I'd expect (especially since the opposite is what happens with usb-otg1).

Note: we don't enable usb-otg2 suspend by default.

To test (it's best to keep the modem off and SD card unused):

echo auto | sudo tee /sys/devices/platform/soc@0/38200000.usb/xhci-hcd.4.auto/power/control
echo auto | sudo tee /sys/devices/platform/soc@0/38200000.usb/power/control