They were talking about the usb modules. The back two on either side (the ones closest to the screen) have an issues where the USB 4 Type C to USB A adapter is not fully going to sleep when nothing is plugged in. So ArsTechnica’s reviewer most likely had one of the USB A modules plugged into those two USB 4 ports which causes their apparent poor battery life.
I believe Framework said they are looking into fixes for this issue, either with firmware patches or if neccesary a hardware revision of the USB A module. Current workaround is just to not put USB A into those two back slots.